One water pump can fill half of a certain empty tank in 8 hours. Another pump can fill half of the same tank in 8.5 hours. Working together, how long will it take these two pumps to fill the entire tank?	Answers: A) 8 7/13 B) 1 5/8 C) 3 1/4 D) 8 8/33 E) 3 1/2
One pump can fill a tank in 8 hours and another in 8.5 hours   so the rate at which both can half fill the tank is (1/8+1/8.5) =&gt; 33/136   Thus half of the tank can be filled in 136/33   so for filling the complete tank =&gt;136/33*2 = 272/33 = 8 8/33   ANSWER:8 8/33
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One water pump can fill half of a certain empty tank in 8 hours. Another pump can fill half of the same tank in 8.5 hours. Working together, how long will it take these two pumps to fill the entire tank?