A and B can together complete a piece of work in 4 days. If A alone can complete the same work in 12 days, in how many days can B alone complete that work ? Choose the correct choice:
A) 4 days  B) 5 days  C) 6 days  D) 7 days  E) 8 days
Explanation:   (A+B)'s 1 day work = 1/4   A's 1 day work = 1/12   B's 1 day work =   (1/4−1/12)=3−1/12=1/6   So B alone can complete the work in 6 days   Option 6 days
<result>C</result>
A and B can together complete a piece of work in 4 days. If A alone can complete the same work in 12 days, in how many days can B alone complete that work ?