Question

6. A and B can do a piece of work in 6 days and 4 days respectively. A started the work, worked at it for 2 days and then was joined by B. Find the total time taken to complete the work ​

Answer 1

Answer:

A can finish work in 6 days

In 1 day A can do 1/6 work

In 1 day B can do 1/4 work

So in 1 day both together can finish 1/6+1/4=5/12 work

A worked for 2 days. In 2 days A will finish (1/6)×2=1/3 work. Remaining amount of work is 1-(1/3)=2/3 which is to be done by both A and B

A and B together can do 5/12 work in 1 day

So 2/3 work can be finished in (2/3)×(12/5) days

=24/15=8/5 days Ans