Question

A can do a work in 30 days while b it in 20 days. If they work together in what time they can finish the work

Answer 1

Work done by A in 30 days = 1 work
Work done by A in 1 day = 1/30 work

work done by B in 20 days = 1 work
work done by B in 1 day = 1/20 work

work done by A and B in 1 day = 1/30+1/20 =1/60 work
Thus , time taken by A and B to finish the work
= 60 days