Question

A, B and C can do a piece of work in 14, 28 and 42 days respectively. They all start doing the work together. A continues to do the work until it is completed, C left 2 days before the work was completed, and B left 1 day before the work was completed. In how many days the work was completed? Select one: a. 95/11 days b. 93/11 days c. 89/11 days d. 91/11 days

Answer 1

Answer:

One day's work of A, B and C = (1/24 + 1/30 + 1/40) = 1/10.

C leaves 4 days before completion of the work, which means only A and B work during the last 4 days.

Work done by A and B together in the last 4 days = 4 (1/24 + 1/30) = 3/10.

Remaining Work = 7/10, which was done by A,B and C in the initial number of days. 

Number of days required for this initial work = 7 days. 

Thus, the total numbers of days required = 4 + 7 = 11 days