Question

P is able to do a piece of work in 15 days and Q can do the same work in 20 days. If they can work together for 4 days, what is the fraction of work left?

Options
1) 8/15
2) 7/15
3) 11/15
4) 2/11

Answer 1

1day's work of p=1/15

1day's work of q=1/20

1day's work of both=7/60

4days work=7/15

remaining work=1-7/15=8/15

Answer 2

Answer:

7/15

Step-by-step explanation:

let P be complete the work of one day for 15 days = 1/ 15

let Q be complete one day for 20 days = 1/ 20

ATQ,

P+Q=1/15 +1/20

=7/60

Together they will take 4 days to complete so, 7/60×4

=7/15

fraction of time left = 1-7/15

=8/15