Question

A, B and C can do a piece of work in 15, 25 and 35 days respectively. In how many

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

Answer 1

Thus in three days the work accomplished is (3/20)+(1/30)+(1/60) = (9/60)+(2/60)+(1/60) = 12/60 or 1/5. So in 3 days, the work completed is 1/5th, so the entire work will be completed in 3/(1/5) = 15 days