Solve.
-Two pipes can be used to fill a pool. Working together, the two pipes can fill the pool in 2 hours. The larger pipe can fill the pool in 3 hours less time than the smaller pipe can alone. Find the time To the nearest tenth of an hour it takes for the smaller pipe working alone to fill the pool.
A) 6.0 hr
B) 3.1 hr
C) 3.0 hr
D) 6.1 hr

Question

Quizplus · Accepted Answer

Let the time it takes for the smaller pipe to fill the pool be $x$ hours. The larger pipe takes $x - 3$ hours. The rate of the smaller pipe is $1/x$ and the rate of the larger pipe is $1/(x - 3)$. Together, their rate is $1/2$ (since they can fill the pool in 2 hours working together). So, $1/x + 1/(x - 3) = 1/2$. Solving this equation gives $x = 6$, which means the smaller pipe takes 6.0 hours to fill the pool alone.

Solve. -Two Pipes Can Be Used to Fill a Pool. Working