A and B together can do a piece of work in 8 days. If A alone can do the same work in 12 days, then B alone can do the same work in?	Choices
A) 49	B) 99	C) 24	D) 88	E) 21

Rationale: b = 1 / 8 – 1 / 2 = 1 / 24 = > 24 days answer : c
Answer: C