X can finish a work in 20 days. Y can finish the same work in 15 days. Yworked for 9 days and left the job. how many days does X alone need to finish the remaining work?  Choices
A) 3	B) 5	C) 6	D) 8	E) 9

Rationale: "work done by x in 1 day = 1 / 20 work done by y in 1 day = 1 / 15 work done by y in 9 days = 9 / 15 = 3 / 5 remaining work = 1 – 3 / 5 = 2 / 5 number of days in which x can finish the remaining work = ( 2 / 5 ) / ( 1 / 20 ) = 8 d"
Answer: D