A group of men decided to do a work in 17 days, but 8 of them became absent. If the rest of the group did the work in 21days, Find the original number of men?
Choose the most appropriate option.
A) 15	B) 20	C) 42	D) 25	E) 18

Rationale: "original number of men = 8 * 21 / ( 21 - 17 ) = 42 answer is c"
Answer: C