## Friday, April 23, 2010

### time and work problems

1.       Work from Days:

 If A can do a piece of work in n days, then A's 1 day's work = 1 . n

2.       Days from Work:

 If A's 1 day's work = 1 , then A can finish the work in n days. n

3.       Ratio:

If A is thrice as good a workman as B, then:

Ratio of work done by A and B = 3 : 1.

Ratio of times taken by A and B to finish a work = 1 : 3

Questions

1. A, B and C can complete a piece of work in 24, 6 and 12 days respectively. Working together, they will complete the same work in:

A.

 1 day 24

B.

 7 day 24

C.

 3 3 days 7

D.

4 days

2. A takes twice as much time as B or thrice as much time as C to finish a piece of work. Working together, they can finish the work in 2 days. B can do the work alone in:

A.

4 days

B.

 6 days

C.

8 days

D.

12 days

3. P can complete a work in 12 days working 8 hours a day. Q can complete the same work in 8 days working 10 hours a day. If both P and Q work together, working 8 hours a day, in how many days can they complete the work?

A.

 5 5 11

B.

 5 6 11

C.

 6 5 11

D.

 6 6 11

4. 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

5. 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 1 days 2

C.

25 days

D.

30 days

6. Sakshi can do a piece of work in 20 days. Tanya is 25% more efficient than Sakshi. The number of days taken by Tanya to do the same piece of work is:

A.

15

B.

 16

C.

18

D.

25

7. A can finish a work in 24 days, B in 9 days and C in 12 days. B and C start the work but are forced to leave after 3 days. The remaining work was done by A in:

A.

5 days

B.

6 days

C.

 10 days

D.

 10 1 days 2

8. X and Y can do a piece of work in 20 days and 12 days respectively. X started the work alone and then after 4 days Y joined him till the completion of the work. How long did the work last?

A.

6 days

B.

 10 days

C.

15 days

D.

20 days

9. A and B together can do a piece of work in 30 days. A having worked for 16 days, B finishes the remaining work alone in 44 days. In how many days shall B finish the whole work alone?

A.

30 days

B.

40 days

C.

 60 days

D.

70 days

10. A alone can do a piece of work in 6 days and B alone in 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

11. 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