Question

A, b and c alone can complete a work in 24, 30 and 20 days respectively. They start the work together. However 6 days and 3 days before the completion of the work a and b leave in that order. In how many days the work will be completed?

Answer 1

a=24, b=30, c=20

let this work is done by a in1day=1/24

and this work is done by b in 1day=1/30

and this work is done by c in 1day=1/20

if they work together so that

1/24+ 1/30 + 1/20 =15/120

1/6+1/3=3/6

3/6-15/120=45/120

so the work will be completed in 45/120