Question

Q.21 :-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 B and C assist him on every third
day?
30
O 12
15
18
s
24

Answer 1

Answer: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 does 1/20th of the work in a day while B does 1/30th and C does 1/60th of the work in a day.

So A works for 3 days and B and C work with him on the third day. 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.