John takes 12 hours to complete a certain job, while Bill takes only 6 hours to complete the same job. If Steve is faster than John but slower than Bill at completing the same job, then which of the following could be the time it takes the three men together, working at their constant, individual rates, to complete the job?  Choose the correct choice:
A) 2 hours, 24 minutes	B) 2 hours, 40 minutes	C) 3 hours, 20 minutes	D) 3 hours, 45 minutes	E) 4 hours, 10 minutes
The rate of John plus Bill is 1/12 + 1/6 = 1/4 of the job completed per hour.   If Steve worked at the same rate as John, the rate would be 1/4 + 1/12 = 1/3   The slowest possible time would be 3 hours.   If Steve worked at the same rate as Bill, the rate would be 1/4 + 1/6 = 5/12   The fastest possible time would be 12/5 hours = 2 hours, 24 minutes.   The actual time is somewhere between these two extreme points.   The answer is 2 hours, 40 minutes.
<result>B</result>
John takes 12 hours to complete a certain job, while Bill takes only 6 hours to complete the same job. If Steve is faster than John but slower than Bill at completing the same job, then which of the following could be the time it takes the three men together, working at their constant, individual rates, to complete the job?