P cando a work in 15 days and Q cando the same work in 20 days. If they can work together for 4 days, what is the fraction of work left? Choose the correct choice from the following:
A) 1/15  B) 2/15  C) 8/15  D) 9/15  E) 11/15
Amount of work P can do in 1 day = 1/15   Amount of work Q can do in 1 day = 1/20   Amount of work P and Q can do in 1 day = 1/15 + 1/20 = 7/60   Amount of work P and Q can together do in 4 days = 4 × (7/60) = 7/15   Fraction of work left = 1 – 7/15= 8/15   8/15
<result>C</result>
P cando a work in 15 days and Q cando the same work in 20 days. If they can work together for 4 days, what is the fraction of work left?