P can do a work in the same time in which Q and R together can do it. If P and Q work together, the work can be completed in 10 days. R alone needs 60 days to complete the same work. then Q alone can do it in Pick one:	A) 20	B) 24	C) 25	D) 27	E) 30

Rationale: "work done by p and q in 1 day = 1 / 10 work done by r in 1 day = 1 / 60 work done by p , q and r in 1 day = 1 / 10 + 1 / 60 = 7 / 60 but work done by p in 1 day = work done by q and r in 1 day . hence the above equation can be written as work done by p in 1 day ã — 2 = 7 / 60 = > work done by p in 1 day = 7 / 120 = > work done by q and r in 1 day = 7 / 120 hence work done by q in 1 day = 7 / 120 â € “ 1 / 60 = 1 / 24 so q alone can do the work in 24 days answer is b ."
Answer: B