Renu can do a piece of work in 6 days, but with the help of her friend Suma , she can do it in 4 days. In what time Suma can do it alone?
Choose the correct choice from the following choices:	A) 10	B) 12	C) 14	D) 15	E) 17

Rationale: "renu ’ s one day ’ s work = 1 / 6 suma ’ s one day ’ s work = 1 / 4 - 1 / 6 = 1 / 12 suma can do it alone in 12 days . answer : b"
Answer: B