X is able to do a piece of work in 14 days and Y can do the same work in 20 days. If they can work together for 5 days, what is the fraction of work completed? Choose the correct option: A) 15 / 28 B) 17 / 28 C) 13 / 28 D) 19 / 28 E) 11 / 28

Rationale: explanation : amount of work x can do in 1 day = 1 / 14 amount of work y can do in 1 day = 1 / 20 amount of work x and y can do in 1 day = 1 / 14 + 1 / 20 = 17 / 140 amount of work x and y can together do in 5 days = 5 × ( 17 / 140 ) = 17 / 28 answer : option b
Answer: B