A and B can together complete a piece of work in 4 days. If A can alone can complete the same work in 12 days, in how many days can B alone complete that work?\nOptions:\n(A) 6\n(B) 5\n(C) 4\n(D) 3\n(E) 2
Let's think step by step.
(A)
(A+B)'s 1 day work = 1/4\nA's 1 day work = 1/12\nB's 1 day work = 1/6.

So, the answer is (A)