Question

One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 minutes, then the slower pipe alone will be able to fill the tank in:
A.81 min.
B.108 min.
C.144 min.
D.192 min.

Answer 1

the answer of this question is

144 minutes..

Answer 2

----: ||ANSWER|| :----

Let the slower pipe alone fill the tank in x minutes

then faster will fill in x/3 minutes.

Part filled by slower pipe in 1 minute = 1/x

Part filled by faster pipe in 1 minute = 3/x

Part filled by both in 1 minute =

$\begin{aligned}</p><p> \bf\frac{1}{x} + \frac{3}{x}= \frac{1}{36} \ \\ \implies \bf \frac{4}{x} = \frac{1}{36} \\</p><p> \bf x = 36 \times 4 = \red{144 \: mins }</p><p>\end{aligned}$