Question

A and B can finish a work on 20 and 30 days respectively. In how many days will they finish the same work​

Answer 1

Answer:

Let, in 20 days A can finish a whole work.

So, in 1 day A can finish 1/20 part of work.

Similarly, in 1 day B can finish 1/30 part of work.

So, in 1 day A & B can finish (1/20 + 1/30) part of work.

ie, 1/12 part of work.

So, A & B together can finish the work in 12 days.

Answer 2

Answer:

30 x 20/(30 + 20) = 600/50 = 12 days. => They work together to complete remaining 25/30 work in : 12 x 25/30 = 10 days.