A and B working together can do a piece of work in 12 days, B and C can do it in 15 days nd C and A can do the same work in 20 days b. How long would each of them take to complete the job?

Explanation

Work done by A and B in 1 day=1/12
Work done by B and C in 1 day=1/15
Work done by C and A 1 day=1/20
Adding all the three, we get, work done by
`2(A+B+C)` in 1 day=`1//12+1//15+1//20=1//5`
`:.` A,B and C can together finish 1/10th of the work in 1 day.
`:.` Work done by A in 1 day=Work done by A,B and C in 1 day-Work done by B and C in 1 day`=1//10-1//15=//30`
`:.` A alone can do it in 30 days.
Work done by B in 1 day=`1//10-1//20=1//20`
`:.` B alone can do it in 20 days.
Work done by C in 1 day`=1//10-1//12=1//60`
`:.` C alone can do it in 60 days.