Pipe P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 1/3 the time that it takes pipe R to do it. If all 3 pipes operating simultaneously but independently are used to drain liquid from the tank, then pipe Q drains what portion of the liquid from the tank?
Choose the correct choice from the following answers
A) 9/29 B) 8/23 C) 9/25 D) 17/29 E) 3/4
Suppose Q can drain in 1 hr. So, rQ = 1/1= 
<gadget id="calculator">1/1</gadget>
<output>1</output>
1   So, rP= 1/[(3/4)rQ] = 4/3   Also, rP = rR/(1/3) =&gt; 4/3 = rR/(1/3) =&gt; rR = 4/9   Let H is the time it takes to drain by running all 3 pipes simultaneously   So combined rate = rC = 1/H = 1 + 4/3 + 4/9 = 25/9 = 1/(9/25)   Thus running simultaneously, Pipe Q will drain 9/25 of the liquid.   Thus answer = 9/25.
<result>C</result>
Pipe P can drain the liquid from a tank in 3/4 the time that it takes pipe Q to drain it and in 1/3 the time that it takes pipe R to do it. If all 3 pipes operating simultaneously but independently are used to drain liquid from the tank, then pipe Q drains what portion of the liquid from the tank?