Exercise – 12

1) A can do a work in 15 days and B in 20 days. If they work on it together for 4 days, then the

fraction of the work that is left is:

a) 1/4 b) 1/10 c) 7/15

d) 8/15 e) None of these

2) A can lay railway track between two given stations in 16 days and B can do the same job in

12 days, with help of C, they did the job in 4 days only. Then, C alone can do the job in:

a) 9 b) 9 c) 9

d) 10 e) None of these

3) A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can

A do the work if he is assisted by B and C on every third day?

a) 12 days b) 15 days c) 16 days

d) 18 days e) None of these

4) A is thrice as good as workman as B and therefore is able to finish a job in 60 days less than

B. Working together, they can do it in:

a) 20 days b) 22 c) 25 days

d) 30 days e) None of these

5) A alone can do a piece of work in 6 days and B alone 8 days. A and B undertook to do it for

Rs.3200. With the help of C, they completed the work in 3 days. How much is to be paid to

C?

a) Rs.375 b) Rs.400 c) Rs.600

d) Rs.800 e) None of these

6) If 6 men and 8 boys can do a piece of work in 10 days while 26 men and 48 boys can do the

same in 2 days, the time taken by 15 men and 20 boys in doing the same type of work will be:

a) 4 days b) 5 days c) 6 days

d) 7 days e) None of these

7) A can do a piece of work in 4 hours; B and C together can do it in 3 hours, while A and C

together can do it in 2 hours. How long will B alone take to do it?

a) 8 hours b) 10 hours c) 12 hours

d) 24 hours e) None of these

8) A can do a certain work in the same time in which B and C together can do it. If A and B

together could do it in 10 days and C alone in 50 days, then B alone could do it in:

a) 15 days b) 20 days c) 25 days

d) 30 days e) None of these

9) A does 80% of a work in 20 days. He then calls in B and they together finish the remaining

work in 3 days. How long B alone would take to do the whole work?

a) 23 days b) 37 days c) 37

d) 40 days e) None of these

10) A machine P can print one lakh books in 8 hours, machine Q can print the same number of

books in 10 hours while machine R can print them in 12 hours. All the machines are started at

9 A.M. while machine P is closed at 11 A.M. and the remaining two machines complete

work. Approximately at what time will the work (to print one lakh books) be finished?

a) 11:30 A.M. b) 12 noon c) 12:30 P.M.

d) 1:00 P.M. e) None of these

11) A can finish a work in 18 days and B can do the same work in 15 days. B worked for 10 days

and left the job. In how many days, A alone can finish the remaining work?

a) 5 b) 5 c) 6

d) 8 e) None of these

12) 4 men and 6 women can complete a work in 8 days, while 3 men and 7 women can complete

it in 10 days. In how many days will 10 women complete it?

a) 35 b) 40 c) 45

d) 50 e) None of thes