Question

A can do a piece of work in 15 days and B in 20 days. With the help of C, the work gets
finished in 5 days. How long will C take to finish the work alone?
A can do a piece of work in 25 days and B can finish it in 20 days. Both started the
work together. After 5 days, A left. In how many days will B finish the remaining​

Answer 1

Answer:

A can do 1/15th of the work in one day

B can do 1/20 work in one day

work done by A and B together in one day: 1/15+1/20 = 7/60 part of the work

work done by A+B+C in one day = 1/5 of the work

C alone does in one day 7/60 - 1/5 = 5/60th part of the work

5/60 = 12 days

Therefore C takes 12 days to finish the work