GRE Prep Club Team Member
Joined: 20 Feb 2017
Posts: 2932
Given Kudos: 1277
GPA: 3.39
Re: A swimming pool is filled using four hoses: Hose P and three additio
[#permalink]
13 Aug 2026, 11:06
Explanation
Let Hose P’s rate be 1 pool per unit time.
Hose P alone fills \(\frac{1}{5}\) of the pool in \(\frac{1}{5}\) of the full filling time.
Each of Q, R, S works at \(\frac{2}{3}\) of P’s rate, so together their rate is \(3*\frac{2}{3}\)=2.
With P, all four hoses have total rate \(1+2=3\) times P’s rate.
The remaining \(\frac{4}{5}\) of the pool therefore takes (4/5)/3=\(\frac{4}{15}\) of P’s full filling time.
Total time:
\(\frac{1}{5}+\frac{4}{15}=\frac{3}{15}+\frac{4}{15}=\frac{7}{15}\)
So the total process takes \(\frac{7}{15}\) of the time Hose P alone would need.
Answer: E