X can finish a work in 36 days. Y can finish the same work in 24 days. Y worked for 12 days and left the job. how many days does X alone need to finish the remaining work? Choose the correct choice from the following answers:
A) 12	B) 13	C) 16	D) 17	E) 18

Rationale: "work done by x in 1 day = 1 / 36 work done by y in 1 day = 1 / 24 work done by y in 12 days = 12 / 24 = 1 / 2 remaining work = 1 – 1 / 2 = 1 / 2 number of days in which x can finish the remaining work = ( 1 / 2 ) / ( 1 / 36 ) = 18 e"
Answer: E