Pumps A, B, and C operate at their respective constant rates. Pumps A and B, operating simultaneously, can fill a certain tank in 1/2 hours; pumps A and C, operating simultaneously, can fill the tank in 1/2 hours; and pumps B and C, operating simultaneously, can fill the tank in 2 hours. How many hours does it take pumps A, B, and C, operating simultaneously, to fill the tank. Pick one:
A) 1/3 B) 1/2 C) 1/4 D) 1 E) 5/6
A+B =1/2 ; A+C =1/2 ,B+C =2 ; ADD TH5/6N 2*(A+B+C) = 3   A+B+C = 3/2 HRS   5/6
<result>E</result>
Pumps A, B, and C operate at their respective constant rates. Pumps A and B, operating simultaneously, can fill a certain tank in 1/2 hours; pumps A and C, operating simultaneously, can fill the tank in 1/2 hours; and pumps B and C, operating simultaneously, can fill the tank in 2 hours. How many hours does it take pumps A, B, and C, operating simultaneously, to fill the tank.