# In How Many Days was the Work Done? If

A, B and C can do a piece of work in 24, 30 and 40 days respectively. They began the work together, but C left 4 days before completion of the work. In how many days was the work done?

- 13
- 14
- 11
- 12

**Answer: (1) 13 **

**Explanation:-
**A can do a piece of work = 24 days

Therefore, A can do work in a day = 1/24

B can do the same work = 30 days

Therefore, B can do work in a day = 1/30

C can do the same work = 40

Therefore, C can do the work in a day =1/40

Then, C can do work in last 4 days = 4/40

= 1/10

Then, the remaining work = 1 – 1/10

= (10 – 1)/10

= 9/10

Time taken by A, B and C to complete the remaining work = 9 x (24 x 30 x 40)/10 x (30 x 40 + 24 x 40 + 24 x 30)

= 9 x 24 x 1200/28800

= 9

Total time taken to complete the work = 9 + 4 = 13 days.

Hence, the answer is (1) 13 days.