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?
Select.
A) 8/15 B) 9/15 C) 11/15 D) 13/17 E) 15
8/15mount of work P can do in 1 day = 1/15   8/15mount of work Q can do in 1 day = 1/20   8/15mount of work P and Q can do in 1 day = 1/15 + 1/20 = 7/60   8/15mount of work P and Q can together do in 4 days = 4 × (7/60) = 7/15   8/15)   Fraction of work left = 1 – 7/15= 8/15
<result>A</result>
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?