Question

Paul and peter can do a piece of work in 60 days, while paul can do it alone in 80 days. how many days will peter take to complete the work alone?

Answer 1

Paul and peter together can do it in 60 days, 1 day work = 1/60

Paul can do it in 80 days, 1 day work = 1/80

1 day work of peter = 1/60 - 1/80 = (4-3) / 240 = 1 / 240

Peter will take 240 days

Answer 2

Paul and Peter can do the piece of work in 60 day

⇒ 1 day = 1/60 of the work

Paul can do it alone in 80 days

⇒ 1 day = 1/80 of the work

Find the amount of work Peter can do in a day:

1 day = 1/60 - 1/80 = 1/240

Find the number of days Peter will need to complete the work:

1/240 of the work = 1 day

240/240 of the work = 1 x 240 = 240 days

Answer: Peter can do the work in 240 days alone.