Math Ncert Exemplar 2019 Solutions for Class 7 Maths Chapter 2 Fractions & Decimals are provided here with simple step-by-step explanations. These solutions for Fractions & Decimals are extremely popular among class 7 students for Maths Fractions & Decimals Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Math Ncert Exemplar 2019 Book of class 7 Maths Chapter 2 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Math Ncert Exemplar 2019 Solutions. All Math Ncert Exemplar 2019 Solutions for class 7 Maths are prepared by experts and are 100% accurate.

Page No 38:

Question 1:

In the given question out of four options, only one is correct. Write the correct answer.
25×515 is equal to :

(a) 2625

(b) 5225

(c) 25

(d) 6

Answer:

25×515 =25×265=2×265×5=5225

Hence, the correct answer is option (b).

Page No 38:

Question 2:

In the given question out of four options, only one is correct. Write the correct answer.
334÷34 is equal to:
(a) 3
(b) 4
(c) 5
(d) 4516

Answer:

334÷34=154×43=5
Hence, the correct answer is option (c).

Page No 38:

Question 3:

A ribbon of length 514m is cut into small pieces each of length 34m. Number of pieces will be:
(a) 5         
(b) 6
(c) 7
(d) 8

Answer:

Total length of ribbon = 514m
Length of each small piece = 34m
∴ Number of pieces =514÷34
=214×43=7
Thus, number of pieces will be 7.

Hence, the correct answer is option (c).



Page No 39:

Question 4:

In the given question out of four options, only one is correct. Write the correct answer.

The ascending arrangement of 23,67,1321 is:
(a) 67,23,1321

(b) 1321, 23,67

(c) 67,1321,23

(d) 23,67,1321

Answer:

LCM of 3, 7 and 21 is 21.
23=2×73×7=1421,67=6×37×3=1821,1321

Now, 
1321<1421<1821 1321<23<67 

Hence, the correct answer is option (b).

Page No 39:

Question 5:

In the given question out of four options, only one is correct. Write the correct answer.
Reciprocal of the fraction 23is:
(a) 2     

(b) 3     

(c) 23     

(d) 32

Answer:

Reciprocal of 23=123=32
Hence, the correct answer is option (d).

Page No 39:

Question 6:

In the given question out of four options, only one is correct. Write the correct answer.
The product 1113 and 4 is:
(a) 3513

(b) 5313

(c) 1335

(d) 1353
 

Answer:

1113×4=1113×41=4413=3513
Hence, the correct answer is option (d).

Page No 39:

Question 7:

In the given question out of four options, only one is correct. Write the correct answer.
The product of 3 and 425 is:
(a) 1725

(b) 245

(c) 1315

(d) 5113

Answer:

3×425=31×225=665=1315
Hence, the correct answer is option (c).

Page No 39:

Question 8:

In the given question out of four options, only one is correct. Write the correct answer.
Pictorial representation of 3×23 is



Answer:

3×23 =2
Thus, the Pictorial representation of 3×23 is

Hence, the correct answer is option (b).

Page No 39:

Question 9:

In the given question out of four options, only one is correct. Write the correct answer.
15÷45equal to:

(a) 45

(b) 15

(c) 54

(d) 14

Answer:

15÷45=15×54=14

Hence, the correct answer is option (d).

Page No 39:

Question 10:

In the given question out of four options, only one is correct. Write the correct answer.
The product of 0.03 × 0.9 is:
(a) 2.7
(b) 0.27
(c) 0.027
(d) 0.0027

Answer:

0.03 × 0.9=3100×910=271000=0.027
Hence, the correct answer is option (c).

Page No 39:

Question 11:

In the given question out of four options, only one is correct. Write the correct answer.
57÷6 is equal to:
(a) 307

(b) 542

(c) 3042

(d) 67

Answer:

57÷6=57×16=542
Hence, the correct answer is option (b).



Page No 40:

Question 12:

In the given question out of four options, only one is correct. Write the correct answer.
516÷92 is equal to
(a) 316

(b) 127

(c) 5127

(d) 3127

Answer:

516÷92 =516×29=316×29=3127

Hence, the correct answer is option (d).

Page No 40:

Question 13:

In the given question out of four options, only one is correct. Write the correct answer.
Which of the following represents 13of 16?
(a) 13+16

(b) 13-16

(c) 13×16

(d) 13÷16
 

Answer:

13of 16=13×16
Hence, the correct answer is option (c).

Page No 40:

Question 14:

In the given question out of four options, only one is correct. Write the correct answer.
37 of 25is equal to

(a) 512

(b) 535

(c) 135

(d) 635

Answer:

table attributes columnalign right center left columnspacing 0px end attributes row cell 3 over 7 space of space 2 over 5 end cell equals cell 3 over 7 cross times space 2 over 5 end cell row blank equals cell 6 over 35 end cell end table
Hence, the correct answer is option (d).

Page No 40:

Question 15:

In the given question out of four options, only one is correct. Write the correct answer.
One packet of biscuits requires 212 cups of flour and 123 cups of sugar. Estimated total quantity of both ingredients used in 10 such packets of biscuits will be
(a) less than 30 cups
(b) between 30 cups and 40 cups
(c) between 40 cups and 50 cups
(d) above 50 cups

Answer:

Flour required in 1 packet = 212 cups
Sugar required in 1 packet = â€‹123 cups
Total quantity of both ingredients used in 1 packet = quantity of flour + quantity of sugar
                                     
  =212+123=52+53=15+106=256=416 cups

Total quantity of both ingredients used in 10 packet = 10 × Total quantity of both ingredients used in 1 packet 
=10×416 cups=10×256 cups=1253 cups=4123 cups

∵ 40 < 4123< 50
Thus, the estimated total quantity of both ingredients used in 10 such packets of biscuits will be between 40 cups and 50 cups.

Hence, the correct answer is option (c).



Page No 41:

Question 16:

In the given question out of four options, only one is correct. Write the correct answer.
The product of 7 and 634 is
(a) 4212

(b) 4714

(c) 4234

(d) 4734

Answer:

7×634=71×274=1894=4714
Hence, the correct answer is option (b).

Page No 41:

Question 17:

In the given question out of four options, only one is correct. Write the correct answer.
On dividing 7 by 25, the result is
(a) 142

(b) 354

(c)  145

(d)   352

Answer:

7÷25=7×52=71×52=352
Hence, the correct answer is option (d).

Page No 41:

Question 18:

In the given question out of four options, only one is correct. Write the correct answer.
223÷5 is equal to
(a) 815

(b) 403

(c) 405

(d) 83

Answer:

223÷5=83÷5=83×15=815
Hence, the correct answer is option (a).

Page No 41:

Question 19:

In the given question out of four options, only one is correct. Write the correct answer.
45 of 5 kg apples were used on Monday. The next day 13 of what was left was used. Weight (in kg) of apples left now is
(a) 27

(b) 114

(c) 23

(d) 421

Answer:

The quantity of apples used on Monday = 45 of 5 kg
                                                                =45×5 kg=4 kg
The quantity of apples left after Monday = 5 kg − 4 kg = 1 kg
The quantity of apples used on the next day, i.e., Tuesday = 13 of what was left was used
                                                                                              =13×1 kg=13 kg

The quantity of apples left after Tuesday =1 kg-13 kg
=3-13kg=23kg

Thus, weight (in kg) of apples left now is 23 kg.
Hence, the correct answer is option (c).
 

Page No 41:

Question 20:

In the given question out of four options, only one is correct. Write the correct answer.



(a) 14÷3

(b) 3×14

(c) 34×3

(d) 3÷14

Answer:

14+14+14=3×14=34

Hence, the correct answer is option (b).

Page No 41:

Question 21:

Fill in the blanks to make the statements true.
Rani ate 27 part of a cake while her brother Ravi ate 45 of the remaining. Part of the cake left is __________

Answer:

Let the whole part of the cake is 1.

Part of the cake Rani ate 27×1=27

∴ Part of the cake left 1-27=7-27=57

Now, part of the cake Ravi ate 45×57=47

Thus, part of the cake left is 47.
 

Page No 41:

Question 22:

Fill in the blanks to make the statements true.
The reciprocal of 37 is __________

Answer:

Reciprocal of 37=137=73

Page No 41:

Question 23:

Fill in the blanks to make the statements true.
23 of 27 is____________

Answer:

23 of 27 =23× 27=2×9=18
Thus, 23 of 27 is  18   .



Page No 42:

Question 24:

Fill in the blanks to make the statements true.
45 of 45 is ___________

Answer:

45 of 45 =45 × 45 =4×9=36
Thus, 45 of 45 is  36 .

Page No 42:

Question 25:

Fill in the blanks to make the statements true.
4×613 is equal to __________

Answer:

4×613 =4×193=763=2513
Thus, 4×613 is equal to 2513 .

Page No 42:

Question 26:

Fill in the blanks to make the statements true.
12 of 427 is__________

Answer:

12 of 427=12× 307=157=217

Thus, 12 of 427 is  217 .

Page No 42:

Question 27:

Fill in the blanks to make the statements true.
19 of 65 is_________

Answer:

19 of 65=19×65=215

Thus, 19 of 65 is  215 .

Page No 42:

Question 28:

Fill in the blanks to make the statements true.
The lowest form of the product 237×79 is __________

Answer:

237×79=177×79=179=189

Thus, 237×79 is  189 .

Page No 42:

Question 29:

Fill in the blanks to make the statements true.
45÷4 is equal to _______

Answer:

45÷4=45×14=15

Thus, 45÷4 is equal to  1 5  .

Page No 42:

Question 30:

Fill in the blanks to make the statements true.
25 of 25 is ________

Answer:

25 of 25 =25×25=10

Thus, 25 of 25 is equals to  10 .

Page No 42:

Question 31:

Fill in the blanks to make the statements true.
15÷56=15_____65

Answer:

15÷56=15  × 65

Page No 42:

Question 32:

Fill in the blanks to make the statements true.
3.2 × 10 = _______

Answer:

3.2×10=3210×10= 32 

Page No 42:

Question 33:

Fill in the blanks to make the statements true.
25.4 × 1000 = _______

Answer:

25.4 × 1000 =25410×1000=25400

Thus, 25.4 × 1000 = 25400.
 

Page No 42:

Question 34:

Fill in the blanks to make the statements true.
93.5 × 100 = _______

Answer:

93.5 × 100 =93510×100=9350

Thus, 93.5 × 100 = 9350

Page No 42:

Question 35:

Fill in the blanks to make the statements true.
4.7 ÷ 10 = ______

Answer:

4.7 ÷ 10 =4710×110= 47100=0.47

Thus, 4.7 ÷ 10 =  0.47  .
 

Page No 42:

Question 36:

Fill in the blanks to make the statements true.
4.7 ÷ 100 = _____

Answer:

4.7÷100=4710×1100=471000=0.047

Thus, 4.7 ÷ 100 =  0.047 .

Page No 42:

Question 37:

Fill in the blanks to make the statements true.
4.7 ÷ 1000 = ______

Answer:

4.7÷1000=4710×11000=4710000=0.0047

Thus, 4.7 ÷ 100 =  0.0047 .

Page No 42:

Question 38:

Fill in the blanks to make the statements true.
The product of two proper fractions is _______ than each of the fractions that are multiplied.

Answer:

The product of two proper fractions is smaller than each of the fractions that are multiplied.

Page No 42:

Question 39:

Fill in the blanks to make the statements true.
While dividing a fraction by another fraction, we _________ the first fraction by the _______ of the other fraction.

Answer:

While dividing a fraction by another fraction, we multiply the first fraction by the reciprocal of the other fraction.

Page No 42:

Question 40:

Fill in the blanks to make the statements true.
8.4 ÷ ______ = 2.1

Answer:

8.4 ÷ ______ = 2.1
Let x be the required number.

8.4 ÷ x= 2.18410× 1x = 21108410×1021= x4= x

Thus, 8.4 ÷ 4 = 2.1 

 



Page No 43:

Question 41:

Fill in the blanks to make the statements true.
52.7 ÷ _______ = 0.527

Answer:

52.7 ÷ _______ = 0.527

Let x be the required number.

52.7 ÷x=0.52752.7 ×1x=0.527527 10÷5271000=x527 10×1000527=x100=x

Thus, 52.7 ÷ 100 = 0.527

Page No 43:

Question 42:

Fill in the blanks to make the statements true.
0.5 _____ 0.7 = 0.35

Answer:

0.5 ×0.7 = 510×710=35100=0.35

Thus, 0.5 × 0.7 = 0.35

Page No 43:

Question 43:

Fill in the blanks to make the statements true.
2 ____53=103

Answer:

2×53=21×53=103

Thus, 2 × 53=103

Page No 43:

Question 44:

Fill in the blanks to make the statements true.
2.001 ÷ 0.003 = __________

Answer:

2.001 ÷ 0.003 = 20011000÷31000= 20011000×10003= 20013=667

Thus, 2.001 ÷ 0.003 = 667

Page No 43:

Question 45:

State whether the statement is True or False.
The reciprocal of a proper fraction is a proper fraction.

Answer:

Let ab be a proper fraction such that a<b.
Reciprocal of ab=1ab=ba
Since, 
b>aba>1ba is an improper fraction

Thus, the reciprocal of a proper fraction is a improper fraction.
So, the statement is False.


 

Page No 43:

Question 46:

State whether the statement is True or False.
The reciprocal of an improper fraction is an improper fraction.

Answer:

Let ab be an improper fraction such that a>b.
Reciprocal of ab=1ab=ba
Since, 
b<aba<1ba is a proper fraction

Thus, the reciprocal of an improper fraction is a proper fraction.
So, the statement is False.

 

Page No 43:

Question 47:

State whether the statement is True or False.
Product of two fractions =Product of their denominatorsProduct of their numerators

Answer:

Let the two fractions be ab andcd.
So, ab×cd=a×cb×d

Thus, Product of two fractions = Product of their numeratorsProduct of their denominators
So, the statement is False.

Page No 43:

Question 48:

State whether the statement is True or False.
The product of two improper fractions is less than both the fractions.

Answer:

Let the two improper fractions be ab andcd where a < b and c < d.
Since, b and c < d
⇒ a × c < b × d
acbd<1

As improper fractions are greater than 1.
Therefore, acbd<1<ab and acbd<1<cd.

Thus, the product of two improper fractions is less than both fractions.

So, the statement is False.

Page No 43:

Question 49:

State whether the statement is True or False.
A reciprocal of a fraction is obtained by inverting it upside down.

Answer:

Let a fraction be ab.
The reciprocal of the fraction ab=1ab=ba.
Thus, the reciprocal of a fraction is obtained by inverting it upside down.
So, the statement is True.
 

Page No 43:

Question 50:

State whether the statement is True or False.
To multiply a decimal number by 1000, we move the decimal point in the number to the right by three places.

Answer:

For example, consider the decimal number 8.9765.
On multiplying 8.9765 by 1000
8.9765 × 1000 = 8976.5
Thus, to multiply a decimal number by 1000, we have moved the decimal point in the number to the right by three places.

So, the statement is True.


 

Page No 43:

Question 51:

State whether the statement is True or False.
To divide a decimal number by 100, we move the decimal point in the number to the left by two places.

Answer:

For example, consider the decimal number 456.7.
On dividing 456.7 by 100
456.7 ÷ 100 = 4.567
Thus, to divide a decimal number by 100, we move the decimal point in the number to the left by two places.
So, the statement is True.

Page No 43:

Question 52:

State whether the statement is True or False.
1 is the only number which is it's own reciprocal.

Answer:

True, 1 is the only number which is it's own reciprocal.

Page No 43:

Question 53:

State whether the statement is True or False.
23 of 8 is same as 23÷8.

Answer:

23of 8=23×81=163

23÷8=23×18=14
16314
∴ 23 of 8 is not same as 23÷8.

So, the statement is False.

Page No 43:

Question 54:

State whether the statement is True or False.
The reciprocal of 47  is 47.

Answer:

The reciprocal of 47 =147=74.

Thus, 47  is not reciprocal of 47 .

Page No 43:

Question 55:

If 5 is added to both the numerator and the denominator of the fraction 59, will the value of the fraction be changed? If so, will the value increase or decrease?

Answer:

Adding 5 to the numerator and denominator of the fraction 59.
5+59+5=1014=57
Yes, the value of the fraction changes.
59<57
Thus, the value increases.

Page No 43:

Question 56:

What happens to the value of a fraction if the denominator of the fraction is decreased while numerator is kept unchanged?

Answer:

The value of a fraction will increase if the denominator of the fraction is decreased while the numerator is kept unchanged.

Page No 43:

Question 57:

Which letter comes 25 of the way among A and J?

Answer:

Letter among A and J are A, B, C, D, E, F, G, H, I, J.
Ttotal letters among A and J =10
25×10=4
∴ 4th letter among A and J = D



Page No 44:

Question 58:

If  23 of a number is 10, then what is 1.75 times of that number?

Answer:

Let the number be x.
23 of x =10x=10×32x=15
1.75 times of the number 15 =1.75 × 15
= 26.25

Thus, 1.75 times of that number is 26.25.

Page No 44:

Question 59:

In a class of 40 students,15 of the total number of students like to eat rice only,25 of the total number of students like to eat chapati only and the remaining students like to eat both. What fraction of the total number of students like to eat both?

Answer:

Total number of students in the class = 40
Fraction of students who like to eat rice only = 15
Number of students who like to eat rice only = 15×40=8
Fraction of students who like to eat chapati only = 25
Number of students who like to eat chapati only = 25×40=16
The total number of students like to eat both = 40 − (8 + 16)
= 40 − 24
= 16

Thus, the total number of students who like to eat both are 16. 
 

Page No 44:

Question 60:

Renu completed 23 part of her home work in 2 hours. How much part of her home work had she completed in 114 hours?

Answer:

Part of her homework in 2 hours = 23
Part of her homework in 1 hours = 23÷2=23×12=13
Part of her homework in 114 hours  = 13×114=13×54=512

Thus, the part of her homework she had completed in 114 hours is 512.

 

Page No 44:

Question 61:

Reemu read 15th pages of a book. If she reads further 40 pages, she would have read 710th pages of the book. How many pages are left to be read?

Answer:

Let total number of pages be x.
Number of pages read by Reemu =15x
According to question,
15x+40=710x710x-15x=407-210x=40510x=4012x=40x=80
Number of pages read by Reemu = 710×80=56

Number of pages left to be read by Reemu = 80-56=24

Page No 44:

Question 62:

Write the number in the box â˜ such that
37×=1598

Answer:

Let the number in the box ☐ be x.
37×x=1598x=1598×73x=514

Page No 44:

Question 63:

Will the quotient 716÷323 be a fraction greater than 1.5 or less than 1.5? Explain.

Answer:

716÷323=436÷113=436×311=4322=1.95

1.95 > 1.5

Thus, the quotient 716÷323 of the given fractions is greater than 1.5.

 

Page No 44:

Question 64:

Describe two methods to compare 1317 and 0.82. Which do you think is easier and why?

Answer:

Method I: Conversion of both numbers 1317 and 0.82 into decimals.
1317 = 0.76 and 0.82 into decimals.

Method II: Conversion of both numbers 1317 and 0.82 into fractions.
0.82=82100=4150 and 1317
 

∴ Method of converting numbers into decimals is easier because it can easily be compared in this method but in other method it is also required to convert the fractions into like fractions to compare the numbers.



Page No 45:

Question 65:

Health: The directions for a pain reliever recommend that an adult of 60 kg and over take 4 tablets every 4 hours as needed, and an adult who weighs between 40 and 50 kg take only 212 tablets every 4 hours as needed. Each tablet weighs 425 gram.
(a) If a 72 kg adult takes 4 tablets, how many grams of pain reliever is he or she receivings?
(b) How many grams of pain reliever is the recommended dose for an adult weighing 46 kg?

Answer:

(a) Each tablet weighs 425 gram
∴Weight of 4 tablets = 425×4 gram=1625 gram

(b) An adult weighing 46 kg takes only 212 tablets.
∴ Weight of 212 tablets =  425×52=25 grams
=425×52gram=25gram

Page No 45:

Question 66:

Animals: The label on a bottle of pet vitamins lists dosage guidelines. What dosage would you give to each of these animals?
(a) a 18 kg adult dog
(b) a 6 kg cat
(c) a 18 kg pregnant dog
graphic missing

Answer:

(a) Total dosage given to a 18 kg adult dog = 12+12 tsp = 1tsp
(b) Total dosage given to a 6 kg cat=6×14=32=112 tsp

(c) Total dosage given to a 18 kg pregnant dog =12×14.5×18=19×18=2 tsp
 

Page No 45:

Question 67:

How many116 kg boxes of chocolates can be made with 112 kg chocolates?

Answer:

116 kg chocolates to be filled in 1 box.
∴ 1 kg chocolates to be filled in 116=1÷116=1×161=16 boxes 

Now, 112 kg chocolates to be filled in 16×112=16×32=24 boxes
 

Page No 45:

Question 68:

Anvi is making bookmarker like the one shown in the given figure. How many bookmarker can she make from a 15 m long ribbon?

Answer:

Length of one bookmarker = 1012 cm=212cm

∴ Number of bookmarkers Anvi can make from 15 m ix., 15 × 100 cm long ribbon
=1212×15×100=221×15×100=10007=142.85 
=142
Thus, Anvi can make 142 bookmaker from a 15 m long ribbon



Page No 46:

Question 69:

A rule for finding the approximate length of diagonal of a square is to multiply the length of a side of the square by 1.414. Find the length of the diagonal when :
(a) The length of a side of the square is 8.3 cm.
(b) The length of a side of the square is exactly 7.875 cm.

Answer:

(a) Length of a side of the square = 83 cm
∴ Length of the diagonal of the square = 1.414 × 8.3 cm
= 11.7362 cm
≈ 11.74 cm

(b) Length of a side of the square = 7.875 cm
Length of the diagonal of the square = 1.414 × 7.875 cm
= 11.13525 cm
≈ 11.14 cm

Page No 46:

Question 70:

The largest square that can be drawn in a circle has a side whose length is 0.707 times the diameter of the circle. By this rule, find the length of the side of such a square when the diameter of the circle is
(a) 14.35 cm     (b) 8.63 cm

Answer:

(a) Diameter of the circle = 14.35 cm 
∴ Length of the side of the square = 0.707 × 14.35 cm
= 10.14545
= 10.15 cm

(b) Diameter of the circle = 8.63 cm
∴ Length of the side of the square = 0.707 × 8.63 cm
= 6.10141 cm
= 6.10 cm

Page No 46:

Question 71:

To find the distance around a circular disc, multiply the diameter of the disc by 3.14. What is the distance around the disc when :
(a) the diameter is 18.7 cm?
(b) the radius is 6.45 cm?

Answer:

(a) Diameter of the disc = 18.7 cm
∴ The distance around the disc = 3.14 × 18.7 cm
= 58.718 cm

(b) Radius of the disc = 6.45 cm
∴ Diameter of the disc = 2 × 6.45 cm = 12.9 cm
∴ The distance around the disc = 3.14 × 12.9 cm
= 40.506 cm

Page No 46:

Question 72:

What is the cost of 27.5 m of cloth at  ₹53.50 per metre?

Answer:

Cost of 1 metre of cloth = ₹53.50
∴ Cost of 27.5 metres of cloth = ₹ (53.50 × 27.5) = ₹1471.25

Page No 46:

Question 73:

In a hurdle race, Nidhi is over hurdle B and 26 of the way through the race, as shown in the Fig. 2.7.

Then, answer the following:
(a) Where will Nidhi be, when she is 46 of the way through the race?
(b) Where will Nidhi be when she is 56 of the way through the race?
(c) Give two fractions to tell what part of the race Nidhi has finished when she is over hurdle C.

Answer:

(a) When Nidhi is 46of the way through the race, she will be at hurdle D.
(b) When Nidhi is 56of the way through the race, she will be at hurdle E.
(c) When Nidhi is over hurdle C, she would finish the 36=12 or middle part of the race.

Page No 46:

Question 74:

Diameter of Earth is 12756000 m. In 1996, a new planet was discovered whose diameter is 586 of the diameter of Earth. Find the diameter of this planet in km.

Answer:

Diameter of Earth = 12756000 m
Diameter of a new planet 586×12756000 m
= 741627.90 m

741627.90 1000km 

= 741.6 km

Thus, the diameter of this planet is 741.6 km.

Page No 46:

Question 75:

What is the product of 5129 and its reciprocal?

Answer:

Reciprocal of 5129=15129=1295
The product of 5129 and its reciprocal = 5129×1295=1
Thus, the product of 5129 and its reciprocal is 1.
 



Page No 47:

Question 76:

Simplify: 212+15212÷15

Answer:

212+15212÷15=52+1552÷15=25+21052×51=2710252=2710×225=27125

Thus, 212+15212÷15=27125 

Page No 47:

Question 77:

Simplify: 14+151-38×35

Answer:

14+151-38×35=520+4201-940=92040-940=9203140=920×4031=1831
Thus, 14+151-38×35=1831

Page No 47:

Question 78:

Divide 310 by 14 of 35

Answer:

310 by 14 of 35=310÷ 14 × 35=310÷ 320=310× 203=2
Thus, 310 by 14 of 35=2

Page No 47:

Question 79:

18 of a number equals 25÷120. What is the number?

Answer:

Let the number be x.
According to the question,
18 of x=25÷12018 × x=25×201 x=25×201×81x=2×4×8 x=64
Thus, the number is x.

Page No 47:

Question 80:

Heena’s father paid an electric bill of â‚¹ 385.70 out of a 500 rupee note. How much change should he have received?

Answer:

The amount of money Heena’s father has = ₹500
He paid an electric bill of ₹385.70
∴ The amount of money he should have received = ₹(500 − 385.70) = ₹114.30
Thus, the change he should have received is â‚¹114.30.
 

Page No 47:

Question 81:

The normal body temperature is 98.6°F. When Savitri was ill her temperature rose to 103.1°F. How many degrees above normal was that?

Answer:

The normal body temperature = 98.6°F
Savitri’s temperature, when she was ill = 103.1°F
∴ Savitri’s temperature above normal = 103.1°F – 98.6°F
= 4.5°F

Page No 47:

Question 82:

Meteorology: One measure of average global temperature shows how each year varies from a base measure. The table shows results for several years.

Year 1958 1964 1965 1978 2002
Difference from Base 0.10°C –0.17°C –0.10°C 1500C 0.54°C
  See the table and answer the following:
(a) Order the five years from coldest to warmest.
(b) In 1946, the average temperature varied by –0.03°C from the base measure. Between which two years should 1946 fall when the years are ordered from coldest to warmest?

Answer:

(a) –0.17°C < –0.10°C < 0.02°C 0.10°C < 0.54°C
–0.17°C < –0.10°C < 1500C < 0.10°C < 0.54°C
The order of five years from coldest to warmest is 1964, 1965, 1978, 1958, 2002.

(b) In 1946, the average temperature varied by 0.03°C.
Since, –0.10°C< –0.03°C1500C

∴ 1946 should fall between 1965 and 1978.



Page No 48:

Question 83:

Science Application
In her science class, Jyoti learned that the atomic weight of Helium is 4.0030; of Hydrogen is 1.0080; and of Oxygen is 16.0000. Find the
difference between the atomic weights of:
(a) Oxygen and Hydrogen
(b) Oxygen and Helium
(c) Helium and Hydrogen

Answer:

The atomic weight of Helium = 4.0030
The atomic weight of Hydrogen = 1.0080
The atomic weight of Oxygen – 16.0000
(a) Difference between the atomic weights of Oxygen and Hydrogen = 16.0000 – 1.0080
= 14.9920
(b) Difference between atomic weights of Oxygen and Helium = 16.0000 – 4.0030 = 11.9970
(c) Difference between atomic weights of Helium and Hydrogen = 4.0030 – 1.0080 = 2.9950

Page No 48:

Question 84:

Measurement made in science lab must be as accurate as possible. Ravi measured the length of an iron rod and said it was 19.34 cm long; Kamal said 19.25 cm; and Tabish said 19.27 cm. The correct length was 19.33 cm. How much of error was made by each of the boys?

Answer:

The correct length of the iron rod = 19.33 cm
The length of the rod measured by Ravi = 19.34 cm
∴ The error made by Ravi = (19.34 − 19.33) cm = +0.01 cm
The length of the rod measured by Kamal = 19.25 cm
∴ The error made by Kamal = (19.25 − 19.33) cm = −0.08 cm
The length of the rod measured by Tabish = 19.27 cm
∴ The error made by Tabish = (19.27 – 19.33) cm = −0.06 cm

Page No 48:

Question 85:

When 0.02964 is divided by 0.004, what will be the quotient?

Answer:

0.02964÷0.004=2964100000÷41000=2964100000×10004=741100=7.41
Thus, when 0.02964 is divided by 0.004, the quotient will be 7.41.

Page No 48:

Question 86:

What number divided by 520 gives the same quotient as 85 divided by 0.625?

Answer:

Let the number be x.
x divided by 520 = 85 divided by 0.625
⇒ ÷ 520 = 85 ÷ 0.625
x520= 850.625x520=136x=136×520x=70720

Thus, the required number is 70720.

Page No 48:

Question 87:

A floor is 4.5 m long and 3.6 m wide. A 6 cm square tile costs ₹ 23.25. What will be the cost to cover the floor with these tiles?

Answer:

Length of the floor = 4.5 m
= (4.5 × 100) cm
= 450 cm

Width of the floor = 3.6 m = (3.6 × 100) cm = 360 cm
∴ Area of the floor = (450 × 360) cm= 162000 cm2

Side of a square tile = 6 cm
∴ Area of one square tile = (6 × 6) cm= 36 cm2
Number of tiles required to cover the floor = Area of floor ÷  Area of one tile =162000 cm÷ 36 cm2
= 4500

Cost of 1 tile = ₹23.25
∴Cost of 4500 tiles = ₹(23.25 × 4500)
= ₹104625

Page No 48:

Question 88:

Sunita and Rehana want to make dresses for their dolls. Sunita has 34m of cloth, and she gave 13 of it to Rehana. How much did Rehana have?

Answer:

Length of cloth Sunita has 34 m
∴ Length of cloth Rehana has 13 of 34 m
=13×34=14m

Thus, Rehana has 14 m of cloth.

Page No 48:

Question 89:

A flower garden is 22.50 m long. Sheela wants to make a border along one side using bricks that are 0.25 m long. How many bricks will be needed?

Answer:

Length of the garden = 22.50 m
Length of one brick = 0.25 m
∴ Number of bricks required to make the border = Length of the garden   Length of one brick
=22.50 m0.25 m=225025=90

Thus, 90 bricks will be needed.

Page No 48:

Question 90:

How much cloth will be used in making 6 shirts, if each required  214m of cloth, allowing 18m for waste in cutting and finishing in each shirt?

Answer:

Length of cloth required for one shirt = 214m + 18m
=94+18=188+18=198=238m

∴ Length of cloth required for 6 shirts= 6×238m

=61×198=574=1414m

Thus, cloth used in making 6 shirts will be 1414m.

Page No 48:

Question 91:

A picture hall has seats for 820 persons. At a recent film show, one usher guessed it was 34 full, another that it was full 23. The ticket office reported 648 sales. Which usher (first or second) made the better guess?

Answer:

Total number of seats = 820
Sale of total tickets = 648

Number of sold tickets guessed by the first usher = 34 of 820
=34×820=615

Number of sold tickets guessed by the second usher = 23 of 820
=23×820=546.67547

Since, 615 is more close to 648 than 547.
Thus, the first usher made the better guess.

Page No 48:

Question 92:

For the celebrating children’s students of Class VII bought sweets for â‚¹740.25 and cold drink for â‚¹ 70. If 35 students contributed equally what amount was contributed by each student?

Answer:

Total spending amount = ₹740.25 + ₹70
= ₹810.25
Total number of students who contributed money = ₹35

Contribution of each student = =810.2535
= ₹23.14

Thus, the equal amount contributed by each student is â‚¹23.14.

Page No 48:

Question 93:

The time taken by Rohan in five different races to run a distance of 500 m was 3.20 minutes, 3.37 minutes, 3.29 minutes, 3.17 minutes and 3.32 minutes. Find the average time taken by him in the races.

Answer:

Total time taken by Rohan in five races = (3.20 + 3.37 + 3.29 + 3.17 + 3.32) minutes
= 16.35 minutes

Total number of races = 5

∴ The average time taken by Rohan = 16.355 minutes = 3.27 minutes



Page No 49:

Question 94:

A public sewer line is being installed along 8014m of road. The supervisor says that the labourers will be able to complete 7.5 m in one day. How long will the project take to complete?

Answer:

Total length of a sewer line 8014m
=3214m
7.5 m long sewer line completed in 1 day.

8014m long sewer line completed in 17.5×3214 days
=1075×3214=15×1072=10710=10.711 days

Thus, the project will get complete in 3 days.

Page No 49:

Question 95:

The weight of an object on moon is 16 its weight on Earth. If an object weighs 535kg on Earth, how much would it weigh on the moon?
figure

Answer:

Weight of the object on Earth = 535 kg
 =285kg
Weight of an object on moon = 16 × weight on Earth
=16×285kg=1415kg=

Page No 49:

Question 96:

In a survey, 200 students were asked what influenced them most to buy their latest CD. The results are shown in the circle graph.
(a) How many students said radio influenced them most?
(b) How many more students were influenced by radio than by a music video channel?
(c) How many said a friend or relative influenced them or they heard the CD in a shop?


 

Answer:

Total number of students = 200

(a) Number of students who were influenced by radio=920×200=90

(b) Number of students who were influenced by music video channel=225×200=16

Number of students who were influenced by radio = 90

∴ Number of students that were influenced more by radio than by a music video channel = 90 − 16 = 74

(c) Numberofstudents who were influenced by friend or relative =320×200=30

Number of students who were influenced by hearing or seeing the CD in a shop=110×200=20

∴ Total number of students who were influenced by both friend or relative and hearing the CD in a shop = 30 + 20 = 50



Page No 50:

Question 97:

In the morning, a milkman filled 512 L of milk in his can. He sold to Renu, Kamla and Renuka 34 L each; to Shadma he sold 78 L; and to Jassi he gave 112 L. How much milk is left in the can?

Answer:

The can of milk filled by the milkman in the morning = 512L=112L 
Milk sold by him to Renu = 34 L
Milk sold by him to Kamla = 34 L
Milk sold by him to Renuka = 34 L
Milk sold by him to Shadma =  78 L
Milk sold by him to Jassi = 112L=32L
Total milk sold by him = 34+34+34+78+32L

                                     =94+78+32L=188+78+128L=18+7+128L=378L 

Milk left in the can = The can of milk filled by the milkman in the morning − Total milk sold by him
                               =112-378L=448-378L=44-378L=78L 

Thus, milk left in the can is 78L
  

Page No 50:

Question 98:

Anuradha can do a piece of work in 6 hours. What part of the work can she do in 1 hour, in 5 hours, in 6 hours?

Answer:

Let the whole work be represented by x.
The part of work done by Anuradha in 6 hours = x
∴ The part of work done by her in 1 hour x6
The part of work done by her in 5 hours = x6× 5 = 5x6
The part of work done by her in 6 hours = x6×6=x
Thus, the work can she do  16th part of the work in 1 hour, 56th part of the work in 5 hours and complete work in 6 hours.

Page No 50:

Question 99:

What portion of a ‘saree’ can Rehana paint in 1 hour if it requires 5 hours to paint the whole saree? In 435 hours? In 312 hours?

Answer:

Let the total portion of the saree be represented by 1.
The portion of saree painted by Rehana in 5 hours = 1
The portion of saree painted by her in 1 hour 1 fifth

Since, 435 hours=235 hours
The portion of saree painted by her in 435 hours=15×435
                                                                             =15×235=2325
Also, 312hours=72hours
The portion of saree painted by her in 312 hours=15×312
                                                                              =15×72=710






 

Page No 50:

Question 100:

Rama has 614kg of cotton wool for making pillows. If one pillow takes 114kg, how many pillows can she make?

Answer:

Quantity of cotton wool Rama has = 614kg=254kg
Quantity of cotton wool one pillow takes = 114kg=54kg
Number of pillows can she make =614kg÷114kg
=254kg÷54kg=254×45=5
Thus, she cam make 5 such pillows.
 

Page No 50:

Question 101:

It takes 213m of cloth to make a shirt. How many shirts can Radhika make from a piece of cloth 913m long?

Answer:

Length of cloth required to make a shirt = 213m=73m
Length of piece of cloth Radhika has = 913m=283m
Number of shirts she can make=913m÷213m
                                                  =283÷73=283×37=4 

Thus, she can make 4 such shirts.

Page No 50:

Question 102:

Ravi can walk 313km in one hour. How long will it take him to walk to his office which is 10 km from his home?

Answer:

Time taken by Ravi to walk 313km = 1 hour 
Time taken by Ravi to walk 1 km = 1÷313
                                                      =1÷103=1×310=310hours
Time taken by Ravi to walk 10 km = 310×10 hours
                                                         = 3 hours

Thus, time taken by him to walk to his office which is 10 km from his home is 3 hours.

 

Page No 50:

Question 103:

Raj travels 360 km on three-fifths of his petrol tank. How far would he travel at the same rate with a full tank of petrol?

Answer:

Distance travelled by Raj with 35thpetrol tank = 360 km
Distance travelled by him with a full petrol tank = 360 km ÷ 35
                                                                             =360×53=120×5=600 km

Thus, at the same rate with a full tank of petrol he can travel 600 km.

Page No 50:

Question 104:

Kajol has â‚¹ 75. This is38 of the amount she earned. How much did she earn?

Answer:

Let the amount earned by Kajol be â‚¹x
Amount she has = â‚¹75
According to the question
38of x=7538×x=75x=75×83x=25×8x=200

Thus, she earns â‚¹200.



Page No 51:

Question 105:

It takes 17 full specific type of trees to make one tonne of paper. If there are 221 such trees in a forest, then
(i) what fraction of forest will be used to make;
(a) 5 tonnes of paper.                   (b) 10 tonnes of paper.
(ii) To save 713 part of the forest how much of paper we have to save.

Answer:

(i) Number of trees required to make one tonne of paper = 17
Total number of trees = 221
∴ Fraction of forest will be used to make one tonne of paper 17 over 221 = 1 over 13
(a) Fraction of forest will be used to make 5 tonnes of paper =113×5=513
(b) Fraction of forest will be used to make 10 tonnes of paper 113×10=1013
(ii) Let we have to save x tonnes of paper to save 713 part of the forest
Fraction of forest will be used to make x tonnes of paper 113×x=x13

Here, x13=713x=7

 

Page No 51:

Question 106:

Simplify and write the result in decimal form :
1÷29+1÷315+1÷223

Answer:

1÷29+1÷315+1÷223=1×92+1÷165+1÷83=1×92+1×516+1×38=92+516+38=7216+516+616=72+5+616=8316=5.1875

Page No 51:

Question 107:

Some pictures (a) to (f) are given below. Tell which of them show:
(1) 2×14                      (2) 2×37                (3) 2×13(4) 14×4                      (5) 3×29               (6) 14×3

Answer:

(1) 2×14 represents the addition of 2 figures, each representing 1 shaded part out of 4 equal parts. Thus, (1) is represented by (d)
(2) 2×37represents the addition of 2 figures, each representing 3 shaded parts out of 7 equal parts. Thus, (2) is represented by (f).(3) 2×13 represents the addition of 2 figures, each representing 1 shaded part out of 3 equal parts. Thus, (3) is represented by (c).
(4) 14×4  represents the addition of 4 figures, each representing 1 shaded part out of 4 equal parts. Thus, (4) is represented by (b).
(5) 3×29 represents the addition of 3 figures, each representing 2 shaded parts out of 9 equal parts. Thus, (5) is represented by (a).
 514×3represents the addition of 3 figures, each representing 1 shaded part out of 3 equal parts. Thus, (6) is represented by (e).



Page No 52:

Question 108:

Evaluate : (0.3) × (0.3) – (0.2) × (0.2)

Answer:

(0.3) × (0.3) – (0.2) × (0.2)
=310×310-210×210=9100-4100=5100=0.05

Thus, (0.3) × (0.3) – (0.2) × (0.2) = 0.05

Page No 52:

Question 109:

Evaluate 0.60.3+0.160.4

Answer:

0.60.3+0.160.4=63+1640=21+25=10+25=125=2.4
Thus, 0.60.3+0.160.4 = 2.4
 

Page No 52:

Question 110:

Find the value of : 0.2×0.14+0.5×0.910.1×0.2

Answer:

0.2×0.14+0.5×0.910.1×0.2=210×14100+510+91100110×210=281000+45510002100=48310002100=4831000×1002=241.510=24.15

Thus, 0.2×0.14+0.5×0.910.1×0.2= 24.15

Page No 52:

Question 111:

A square and an equilateral triangle have a side in common. If side of triangle is 43cm long, find the perimeter of figure formed

 

Answer:

Side of the equilateral triangle = 43cm
∴ Side of the square = 43cm

∴ Perimeter of the figure formed = 43+43+43+43+43 cm
=203 cm=623cm

Thus,  the perimeter of figure formed is 623cm.
 

Page No 52:

Question 112:

Rita has bought a carpet of size 4 m × 623m. But her room size is 313m ×  513m. What fraction of area should be cut off to fit wall to wall carpet into the room?

Answer:

 Area of the carpet bought by Rita = 4 m × 623m
                                                      =41×203m2=803m2
Area of the room = 313m ×  513m
                           =103×163m2=1609m2

Area to be cut off to fit wall to wall carpet into the room = 803-1609m2
                                                                                          =2409-1609m2=240-1609m2=809m2=889m2

Thus, area to be cut off to fit wall to wall carpet into the room is 889m2.

Page No 52:

Question 113:

Family photograph has length 1425cm and breadth 1025cm. It has border of uniform width 235cm. Find the area of framed photograph.

Answer:

Length of the photograph = 1425cm =725cm
Breadth of the photograph = 1025cm=525cm
Width of the boarded = 235 cm = 135cm
Length of the framed photograph =725+135+135cm=985cm
Breadth of the framed photograph =525+135+135cm=785cm

Area of the framed photograph =985×785cm2
                                                =764425cm2=3051925cm2

Page No 52:

Question 114:

Cost of a burger is ₹ 2034 and of Macpuff is ₹ 1512 . Find the cost of 4 burgers and 14 macpuffs.

Answer:

Cost of 1 burger = ₹2034 
Cost of 4 burger = ₹2034 × 4
                          =834×4=83

Cost of 1 Macpuff = ₹ 1512
Cost of 14 Macpuff = ₹ 1512 × 14
                               =312×14=217

So, the cost of 4 burgers and 14 macpuffs = â‚¹83 + â‚¹217
= â‚¹300

Thus, the cost of 4 burgers and 14 macpuffs is â‚¹300.  
 

Page No 52:

Question 115:

A hill,10113 m in height, has 14th of its height under water. What is the height of the hill visible above the water?

Answer:

Total height of hill = 10113 m
Height of hill under water = 14th of the height of the hill 
                                          =14×3043m=763m

Height of hill above water=10113-763m
                                          =3043-763m=2283m=76 m



Thus, the height of the hill visible above the water is 76 m.

Page No 52:

Question 116:

Sports: Reaction time measures how quickly a runner reacts to the starter pistol. In the 100 m dash at the 2004 Olympic Games, Lauryn Williams had a reaction time of 0.214 second. Her total race time, including reaction time, was 11.03 seconds. How long did it take her to run the actual distance?

Answer:

Total race time of Lauryn Williams = 11.03 seconds
Her reaction time = 0.214 second
Time taken by her to run the actual distance = (11.03 – 0.214) seconds
                                                                       = 10.816 seconds



Page No 53:

Question 117:

State whether the answer is greater than 1 or less than 1. Put a ‘✓’ mark in appropriate box.

Questions Greater than 1 Less than 1
23÷12    
23÷21    
6÷14    
15÷12    
413÷312    
23×812    

Answer:

(i) 
23÷12=23×21=43>1

(ii) 
23÷21=23×12=13<1

(iii)
6÷14=6×41=24>1

(iv)
15÷12=15×21=25<1

(v)
413÷312=133÷72=133×27=2621>1

(vi)
23×812=23×172=173>1
 

Page No 53:

Question 118:

There are four containers that are arranged in the ascending order of their heights. If the height of the smallest container given in the figure is expressed as725x = 10.5 cm. Find the height of the largest container.

Answer:

Height of the smallest container = 10.5 cm
We have given that
725x=10.5x=10.5×257x=10510×257x=152×51x=37.5 cm

∴ Height of the largest container is 37.5 cm.

Page No 53:

Question 119:

In the given question replace ‘?’ with appropriate fraction.

Answer:

In the given figure a pattern is formed
78724=78×3772=724×37216=772×3?=7216×3=7648

Page No 53:

Question 120:

In the given question replace ‘?’ with appropriate fraction.

Answer:

In the given figure a pattern is formed
332316=332÷238=316÷234=38÷2?=34÷2=32



Page No 54:

Question 121:

In the given question replace ‘?’ with appropriate fraction.

Answer:

In the given figure a pattern is formed
0.050.5=0.05×105=0.5×1050=5×10?=50×10=500

Page No 54:

Question 122:

In the given question replace ‘?’ with appropriate fraction.

Answer:

In the given figure a pattern is formed
0.10.01=0.1100.001=0.01100.0001=0.00110?=0.000110=0.00001

Page No 54:

Question 123:

What is the Error in the given question.
A student compared -14and –0.3. He changed -14 to the decimal –0.25 and wrote, “Since 0.3 is greater than 0.25, –0.3 is greater than –0.25”. What was the student’s error?

Answer:

Since 0.3 is greater than 0.25.
∴ −0.3 is less than −0.25
Thus, the error is −0.30 > −0.25

Page No 54:

Question 124:

What is the Error in the given question.
A student multiplied two mixed fractions in the following manner:
247×314=617 ,What error the student has done?

Answer:

247×314=187×134=97×132=11714=8514
But student has multiplied two mixed fractions 247and 314to get 617.
So, the student has done error that mixed fractions are not converted into improper fractions.

Page No 54:

Question 125:

What is the Error in the given question.

In the pattern 13+14+15+...........which fraction makes the sum greater than 1 (first time)? Explain.

Answer:

The given pattern is 13+14+15+...........
Case I: 

13+14+15=2060+1560+1260=20+15+1260=4760<1

Case II: 

13+14+15+16=2060+1560+1260+1060=20+15+12+1060=5760<1
Case III: 

13+14+15+16+17=140420+105420+84420+70420+60420=140+105+84+70+60420=459420>1


Thus, in the pattern 13+14+15+...........thr fraction that makes the sum greater than 1 (first time) is 17.
 



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