X can do a piece of work in 40days. He works at it for 8 days and then Y finished it in 24 days. How long will Y take to complete the work?
Choose the correct choice from the following answers:
A) 30 B) 12 C) 15 D) 18 E) 20

Rationale: "work done by x in 8 days = 8 * 1 / 40 = 1 / 5 remaining work = 1 - 1 / 5 = 4 / 5 4 / 5 work is done by y in 24 days whole work will be done by y in 24 * 5 / 4 = 30 days answer is a"
Answer: A