P alone can complete a job in 12 days. The work done by Q alone in one day is equal to one-half of the work done by P alone in one day. In how many days can the work be completed if P and Q work together?	Choose one:
A) 5 B) 6 C) 7 D) 8 E) 9
P's rate is 1/12   Q's rate is 1/24   The combined rate is 1/12 + 1/24 = 1/8   If they work together, the job will take 8 days.   The answer is 8.
<result>D</result>
P alone can complete a job in 12 days. The work done by Q alone in one day is equal to one-half of the work done by P alone in one day. In how many days can the work be completed if P and Q work together?