It takes 6 beavers 10 hours to build a certain dam, working at a uniform rate. If six beavers start to build the same dam at noon, and one beaver per hour is added beginning at 5:00 PM, at what time will the dam be complete?	Choose the correct choice from the following options.
A) 7:24 PM	B) 8:00 PM	C) 8:36 PM	D) 9:12 PM	E) 9:48 PM
The rate of 1 beaver is 1/60.   The amount of work done by 6 beavers in 5 hours is 6/60 *5 = 30/60   In the next hour, 7 beavers do 7/60 for a total of 37/60.   In the next hour, 8 beavers do 8/60 for a total of 45/60.   In the next hour, 9 beavers do 9/60 for a total of 54/60.   In the next 36 minutes, 10 beavers do 10/60 * 36/60 = 6/60 for a total of 60/60.   The dam will be completed at 8:36 pm.   The answer is 8:36 PM.
<result>C</result>
It takes 6 beavers 10 hours to build a certain dam, working at a uniform rate. If six beavers start to build the same dam at noon, and one beaver per hour is added beginning at 5:00 PM, at what time will the dam be complete?