Working at a constant rate, P can finish a job in 3 hours. Q, also working at a constant rate, can finish the same job in 15 hours. If they work together for 2 hours, how many more minutes will it take P to finish the job, working alone at his constant rate? Select:
A) 30
B) 36
C) 40
D) 45
E) 48
Each hour they complete 1/3 + 1/15 = 2/5 of the job.   In 2 hours, they complete 2(2/5) = 4/5 of the job.   The time for P to finish is (1/5) / (1/3) = (3/5) hour = 36 minutes   The answer is 36.
<result>B</result>
Working at a constant rate, P can finish a job in 3 hours. Q, also working at a constant rate, can finish the same job in 15 hours. If they work together for 2 hours, how many more minutes will it take P to finish the job, working alone at his constant rate?