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

 a) 8/15
 b) 3/22
 c) 6/15
 d) 2/9

8/15. Solution Work done by Tony in 1 day = 1/15 Work done by Kevin in 1 day = 1/20 Amount of work Tony and Kevin can do in 1 day = 1/15 + 1/20 = 7/60 Amount of work Praveen and Qureshi can together do in 4 days = 4 × (7/60) = 7/15 Fraction of work left = 1 – 7/15= 8/15