# RD Sharma (2014) Solutions for Class 7 Math Chapter 10 - Unitary Method

RD Sharma (2014) Solutions for Class 7 Math Chapter 10 Unitary Method are provided here with simple step-by-step explanations. These solutions for Unitary Method are extremely popular among class 7 students for Math Unitary Method Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the RD Sharma (2014) Book of class 7 Math Chapter 10 are provided here for you for free. You will also love the ad-free experience on Meritnation’s RD Sharma (2014) Solutions. All RD Sharma (2014) Solutions for class 7 Math are prepared by experts and are 100% accurate.

#### Page No 10.2:

#### Question 1:

20 chocolates cost Rs 320. Find the cost of 35 such chocolates.

#### Answer:

Cost of 20 chocolates = Rs. 320

Cost of 1 chocolate = Rs. 320 ÷ 20 = 16

So, cost of 35 chocolates = 35 × 16 = Rs. 560

#### Page No 10.2:

#### Question 2:

The cost of 40 metres of cloth is Rs 200. Find the cost of 50 metres of cloth.

#### Answer:

Cost of 40 metres of cloth = Rs. 200

Therefore, cost of 1 metre of cloth = Rs. $200\xf740=\mathrm{Rs}.5$

Hence, cost of 50 metres of cloth = Rs. 5(50) = Rs. 250

#### Page No 10.2:

#### Question 3:

A car can cover a distance of 522 km on 36 litres of petrol. How far can it travel on 14 litres of petrol?

#### Answer:

Distance covered by the car on 36 litres = 522 km

Distance covered by the car on 1 litre = 522 ÷ 36

Distance covered by the car on 14 litres = (522 ÷ 36) × 14 = 203 km

#### Page No 10.2:

#### Question 4:

Travelling 900 km by rail costs Rs 280. What would be the fare for a journey of 360 km when a person travels by the same class?

#### Answer:

Fare for 900 km of rail travel = Rs. 280

Fare for 1 km = Rs. 280 ÷ 900

Therefore, fare for 360 km = (280 ÷ 900) × 360 = Rs. 112

#### Page No 10.2:

#### Question 5:

If 6 oil tankers can be filled by a pipe in 4 $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.$ hours, how long does the pipe take to fill 4 such oil tankers?

#### Answer:

Time taken by the pipe to fill 6 oil tankers = 4 1/2 = 9/2 hours

Time taken to fill 1 oil tanker = $\frac{9}{2}\times \frac{1}{6}=\frac{3}{4}\mathrm{hours}$

Therefore, the pipe will be able to fill 4 oil tankers in $\frac{3}{4}\times 4=3\mathrm{hours}.$

#### Page No 10.2:

#### Question 6:

3/4 of the salary per month is Rs 600. What is the salary per month?

#### Answer:

Let the salary be Rs. x.

Then, 3/4 of the salary per month = Rs. 600.

That is, (3/4) *x = *600

⇒ *x *= (4 × 600) ÷ 3 = Rs. 800

So, the salary = Rs. 800.

#### Page No 10.2:

#### Question 7:

The cost of 32 tables is Rs 23520. Find the number of such tables that can be purchased for Rs 51450.

#### Answer:

With Rs. 23520, we can buy 32 tables.

Therefore, with Re. 1, we can buy $\frac{32}{23520}$ tables.

Hence, the number of tables that we can purchase with Rs. 51450 = $\frac{2}{23520}\times 51450$ = 70.

#### Page No 10.2:

#### Question 8:

The yield of wheat from 6 hectares is 280 quintals. Find the number of hectares required for a yield of 225 quntals.

#### Answer:

Yield of wheat from 6 hectares = 280 quintals

Yield of wheat from 1 hectare = 280 ÷ 6 = 46.66 quintals

Number of hectares required for a yield of 225 quintals = 225 ÷ 46.66 = 4.8 hectares

So, 4.8 hectares is required for a yield of 225 quintals.

#### Page No 10.2:

#### Question 9:

Fifteen post cards cost Rs 2.25. What will be the cost of 36 post cards? How many postcards can we buy in Rs 45?

#### Answer:

Cost of 15 postcards = Rs. 2.25

Cost of 1 postcard = Rs. 2.25 ÷ 15 = Rs. 0.15

Cost of 36 postcards = 36 × (2.25 ÷ 15) = Rs. 5.4

Number of postcards that can be bought for Rs. 45 = 45 ÷ 0.15 = 300

#### Page No 10.2:

#### Question 10:

A rail journey of 75 km costs Rs 215. How much will a journey of 120 km cost?

#### Answer:

Fare for a rail journey of 75 km = Rs. 215

Fare for 1 km = Rs. 215 ÷ 75 = Rs. 2.86

Fare for 120 km = Rs. 120 × 2.86 = Rs. 343.2

#### Page No 10.3:

#### Question 11:

If the sales tax on a purchase wirth Rs 60 is Rs 4.20. What will be the sales tax on the purchase worth of Rs 150?

#### Answer:

Sales tax on purchase worth Rs. 60 = Rs. 4.20

Sales tax on purchase worth Re. 1 = 4.20 ÷ 60

Therefore, sales tax on purchase worth Rs. 150 = Rs. 150 × (4.20 ÷ 60) = Rs. 10.5.

#### Page No 10.3:

#### Question 12:

52 packets of 12 pencils each, cost Rs 499.20. Find the cost of 65 packets of 10 pencils each.

#### Answer:

Cost of 52 packets of 12 pencils each = Rs. 499.20

Cost of 1 packet of 12 pencils = Rs. 499.20 ÷ 52 = Rs. 9.6

Therefore, cost of 12 pencils = Rs. 9.6

So, cost of 1 pencil = Rs. 9.6 ÷ 12 = Rs. 0.8

Cost of 10 pencils = Rs. 10 × (9.6 ÷ 12) = Rs. 8

Therefore, cost of 1 packet of 10 pencils each = Rs. 8

Hence, cost of 65 packets of 10 pencils each = 65 × Rs. 8 = Rs. 520

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