Page No 172:
Question 1:
Rajan can do a piece of work in 24 days while Amit can do it in 30 days. In how many days can they complete it, if they work together?
Answer:
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Question 2:
Ravi can do a piece of work in 15 hours while Raman can do it in 12 hours. How long will both take to do it, working together?
Answer:
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Question 3:
A and B, working together can finish a piece of work in 6 days, while A alone can do it in 9 days. How much time will B alone take to finish it?
Answer:
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Question 4:
Two motor mechanics, Raju and Siraj, working together can overhaul a scooter in 6 hours. Raju alone can do the job in 15 hours. In how many hours can Siraj alone do it?
Answer:
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Question 5:
A, B and C can do a piece of work in 10 days, 12 days and 15 days respectively. How long will they take to finish it if they work together?
Answer:
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Question 6:
A can do a piece of work in 24 hours while B alone can do it in 16 hours. If A, B and C working together can finish it in 8 hours, in how many hours can C alone finish the work?
Answer:
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Question 7:
A, B and C working together can finish a piece of work in 8 hours. A alone can do it in 20 hours and B alone can do it in 24 hours. In how many hours will C alone do the same work?
Answer:
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Question 8:
A and B can finish a piece of work in 16 days and 12 days respectively. A started the work and worked at it for 2 days. He was then joined by B. Find the total time taken to finish the work.
Answer:
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Question 9:
A can do a piece of work in 14 days while B can do it in 21 days. They began together and worked at it for 6 days. Then, A fell ill and B had to complete the remaining work alone. In how many days was the work completed?
Answer:
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Question 10:
A can do of a certain work in 16 days and B can do of the same work in 3 days. In how many days can both finish the work, working together?
Answer:
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Question 11:
A, B and C can do a piece of work in 15, 12 and 20 days respectively. They started the work together, but C left after 2 days. In how many days will the remaining work be completed by A and B?
Answer:
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Question 12:
A and B can do a piece of work in 18 days; B and C can do it in 24 days while C and A can finish it in 36 days. In how many days can A, B, C finish it, if they all work together?
Answer:
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Question 13:
A and B can do a piece of work in 12 days, B and C in 15 days, and C and A in 20 days. How much time will A alone take to finish the job?
Answer:
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Question 14:
Pipes A and B can fill an empty tank in 10 hours and 15 hours respectively. If both are opened together in the empty tank, how much time will they take to fill it completely?
Answer:
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Question 15:
Pipe A can fill an empty tank in 5 hours while pipe B can empty the full tank in 6 hours. If both are opened at the same time in the empty tank, how much time will they take to fill it up completely?
Answer:
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Question 16:
Three taps A, B and C can fill an overhead tank in 6 hours, 8 hours and 12 hours respectively. How long would the three taps take to fill the empty tank, if all of them are opened together?
Answer:
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Question 17:
A cistern has two inlets A and B which can fill it in 12 minutes and 15 minutes respectively. An outlet C can empty the full cistern in 10 minutes. If all the three pipes are opened together in the empty tank, how much time will they take to fill the tank completely?
Answer:
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Question 18:
A pipe can fill a cistern in 9 hours. Due to a leak in its bottom, the cistern fills up in 10 hours. If the cistern is full, in how much time will it be emptied by the leak?
Answer:
The leak will empty the filled cistern in 90 hours.
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Question 19:
Pipe A can fill a cistern in 6 hours and pipe B can fill it in 8 hours. Both the pipes are opened and after two hours, pipe A is closed. How much time will B take to fill the remaining part of the tank?
Answer:
Page No 174:
Question 1:
Tick (✓) the correct answer:
A alone can do a piece of work in 10 days and B alone can do it in 15 days. In how many days will A and B together do the same work?
(a) 5 days
(b) 6 days
(c) 8 days
(d) 9 days
Answer:
(b) 6 days
Page No 174:
Question 2:
Tick (✓) the correct answer:
A man can do a piece of work in 5 days. He and his son working together can finish it in 3 days. In how many days can the son do it alone?
(a) days
(b) 7 days
(c) days
(d) 8 days
Answer:
(c)
Page No 174:
Question 3:
Tick (✓) the correct answer:
A can do a job in 16 days and B can do the same job in 12 days. With the help of C, they can finish the job in 6 days only. Then, C alone can finish it in
(a) 34 days
(b) 22 days
(c) 36 dyas
(d) 48 days
Answer:
(d) 48 days
Page No 174:
Question 4:
Tick (✓) the correct answer:
To complete a work, A takes 50% more time than B. If together they take 18 days to complete the work, how much time shall B take to do it?
(a) 30 days
(b) 35 days
(c) 40 days
(d) 45 days
Answer:
(a) 30 days
Page No 174:
Question 5:
Tick (✓) the correct answer:
A works twice as fast as B. If both of them can together finish a piece of work in 12 days, then B alone can do it in
(a) 24 days
(b) 27 days
(c) 36 days
(d) 48 days
Answer:
(c) 36 days
Page No 174:
Question 6:
Tick (✓) the correct answer:
A alone can finish a piece of work in 10 days which B alone can do in 15 days. If they work together and finish it, then out of total wages of Rs 3000, A will get
(a) Rs 1200
(b) Rs 1500
(c) Rs 1800
(d) Rs 2000
Answer:
(c) Rs. 1800
Since the wage distribution will follow the work distribution ratio, we have:
Work done by A in 1 day
Work done by B in 1 day
Net work done by (A+B) in 1 day
i.e., (A+B) will take 6 days to complete the work.
A's share of work in a day =
∴ A's wage =
Page No 174:
Question 7:
Tick (✓) the correct answer:
The rates of working of A and B are in the ratio 3 : 4. The number of days taken by them to finish the work are in the ratio
(a) 3 : 4
(b) 9 : 16
(c) 4 : 3
(d) 16 : 9
Answer:
(c) 4:3
The number of days taken for working is the reciprocal of the rate of work.
Page No 174:
Question 8:
Tick (✓) the correct answer:
A and B together can do a piece of work in 12 days; B and C can do it in 20 days while C and A can do it in 15 days. A, B and C all working together can do it in
(a) 6 days
(b) 9 days
(c) 10 days
(d) days
Answer:
(c) 10 days
Page No 174:
Question 9:
Tick (✓) the correct answer:
3 men or 5 women can do a work in 12 days. How long will 6 men and 5 women take to do it?
(a) 6 days
(b) 5 days
(c) 4 days
(d) 3 days
Answer:
(c) 4 days
The work can be completed in 4 days.
Page No 174:
Question 10:
Tick (✓) the correct answer:
A can do a piece of work in 15 days. B is 50% more efficient than A. A can finish it in
(a) 10 days
(b) days
(c) 12 days
(d) days
Answer:
(a) 10 days
Page No 175:
Question 11:
Tick (✓) the correct answer:
A does 20% less work than B. If A can finish a piece of work in hours, then B can finish it in
(a) 5 hours
(b) hours
(c) 6 hours
(d) hours
Answer:
(c) 6 hours
Page No 175:
Question 12:
Tick (✓) the correct answer:
A can do a piece of work in 20 days which B alone can do in 12 days. B worked at it for 9 days. A can finish the remaining work in
(a) 3 days
(b) 5 days
(c) 7 days
(d) 11 days
Answer:
(b) 5 days
Page No 175:
Question 13:
Tick (✓) the correct answer:
A can do a piece of work in 25 days, which B alone can do in 20 days. A started the work and was joined by B after 10 days. The work lasted for
(a) days
(b) 15 days
(c) days
(d) 14 days
Answer:
(c)
Page No 175:
Question 14:
Tick (✓) the correct answer:
Two pipes can fill a tank in 20 minutes and 30 minutes respectively. If both the pipes are opened simultaneously, then hte tank will be filled in
(a) 10 minutes
(b) 12 minutes
(c) 15 minutes
(d) 25 minutes
Answer:
(b) 12 minutes
Page No 175:
Question 15:
Tick (✓) the correct answer:
A tap can fill a cistern in 8 hours and another tap can empty the full cistern in 16 hours. If both the taps are open, the time taken to fill the cistern is
(a) hours
(b) 10 hours
(c) 16 hours
(d) 20 hours
Answer:
(c) 16 hours
Page No 175:
Question 16:
Tick (✓) the correct answer:
A pump can fill a tank in 2 hours. Due to a leak in the tank it takes hours to fill the tank. The leak can empty the full tank in
(a) hours
(b) 7 hours
(c) 8 hours
(d) 14 hours
Answer:
(d) 14 hours
Page No 175:
Question 17:
Tick (✓) the correct answer:
Two pipes can fill a tank in 10 hours and 12 hours respectively, while a third pipe empties the full tank in 20 hours. If all the three pipes operate simultaneously, in how much time will the tank be full?
(a) 7 hrs 15 min
(b) 7 hrs 30 min
(c) 7 hrs 45 min
(d) 8 hrs
Answer:
(b) 7 hours 30 minutes
Page No 176:
Question 1:
A can do a piece of work in 10 days while B alone can do it in 15 days. In how many days can both finish the same work?
Answer:
Page No 176:
Question 2:
A and B can do a piece of work in 15 days; B and C in 12 days; C and A in 20 days. How many days will be taken by A, B and C working together to finish the work?
Answer:
Page No 176:
Question 3:
Tap A can fill a cistern in 8 hours and tap B can empty it in 12 hours. How long will it take to fill the cistern if both of them are opened together?
Answer:
Page No 176:
Question 4:
2 men or 3 women can do a piece of work in 16 days. In how many days can 4 men and 6 women do the same work?
Answer:
Page No 176:
Question 5:
A pipe can fill a cistern in 9 hours. Due to a leak in its bottom, the cistern fills up in 10 hours. If the cistern is full, in how much time will it be emptied by the leak?
Answer:
Page No 176:
Question 6:
Mark (✓) against the correct answer:
The rates of working of two tapes A and B are in the ratio 2 : 3. The ratio of the time taken by A and B respectively to fill a given cistern is
(a) 2 : 3
(b) 3 : 2
(c) 4 : 9
(d) 9 : 4
Answer:
(b) 3:2
Page No 176:
Question 7:
Mark (✓) against the correct answer:
A can finish a piece of work in 12 hours while B can finish it in 15 hours. How long will both take to finish it, working together?
(a) 9 hours
(b) hours
(c) hours
(d) hours
Answer:
(b)
Page No 176:
Question 8:
Mark (✓) against the correct answer:
A can do a piece of work in 14 days and B is 40% more efficient than A. In how many days can B finish it?
(a) 10 days
(b) days
(c) days
(d) days
Answer:
(a) 10 days
Page No 176:
Question 9:
Mark (✓) against the correct answer:
A pump can fill a cistern in 2 hours. Due to a leak in the tank it takes hours to fill it. The leak can empty the full tank in
(a) 7 hours
(b) 14 hours
(c) 8 hours
(d) 3 hours
Answer:
(b) 14 hours
Page No 176:
Question 10:
Mark (✓) against the correct answer:
A works twice as fast as B. If both of them can together finish a peice of work in 12 hours, then B alone can do it in
(a) 24 hours
(b) 27 hours
(c) 36 hours
(d) 18 hours
Answer:
(c) 36 hours
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Question 11:
Fill in the blanks.
(i) A tap can fill a tank in 6 hours. The part of the tank filled in 1 hour is .........
(ii) A and B working together can finish a piece of work in 6 hours while A alone can do it in 9 hours. B alone can do it in ......... hours.
(iii) A can do a work in 16 hours and B alone can do it in 24 hours. If A, B and C working together can finish it in 8 hours, then C alone can finish it in ......... hours.
(iv) If A's one day's work is , then A can finish the whole work in ......... days.
Answer:
(i) A tap can fill a tank in 6 hours. In 1 hour, of the tank is filled.
(ii) 18 hours
(iii) 48 hours
(iv) The time for completion is the reciprocal of the work done in one day. Therefore, A can complete the whole work in
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