Question

A can do a work in 25 days and b can do 20 days , after they work together for 5 days a goes away , the number of days requere to complete work

Answer 1

A can do a work in= 1/25 days

B can do the work in= 1/20 days

In 5 days both do work = 5*(1/25)+5*(1/20) = 1/5+1/4 = 9/20

So 9/20 work is completed in 5 days.

Now, remaining work=1–9/20 = 11/20

So B will complete work in = (11/20)/(1/20)=11 days