General TestPipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in :

Pipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in :

A
$1 \frac{13}{17} hours$
B
$2 \frac{8}{11} hours$
C
$3 \frac{9}{17} hours$
D
$4 \frac{1}{2} hours$

Solution:

Net part filled in 1 hour

$= (\frac{1}{5} + \frac{1}{6} - \frac{1}{12}) = \frac{17}{60}$

$∴$ The tank will be full in $\frac{60}{17} hrs i.e., 3 \frac{9}{17} hrs.$