Question

A can do a piece of work in 10 days and b can do the same work in 20 days. With the help of c, they finish the work in 5 days . How long will it takes for c to complete alone

Answer 1

A= 10 (2)
B= 20(1)
A+B+C=5 (4)
total work= 20
c= 20/1= 20 days will be the answer