P alone can complete a job in 4 days. The work done by Q alone in one day is equal to one-third 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 the correct choice from the following answers:
A) 1.5 B) 2.0 C) 2.5 D) 3.0 E) 3.5
P's rate is 1/4   Q's rate is 1/12   The combined rate is 1/4 + 1/12 = 1/3   If they work together, the job will take 3 days.   The answer is 3.0.
<result>D</result>
P alone can complete a job in 4 days. The work done by Q alone in one day is equal to one-third 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?