Miscellaneous Question 101
- When a tank is one-third full, pipe A can fill the tank in 10 minutes and pipe $B$ can empty the full tank in 6 minutes. If both the pipes are opened simultaneously, then how long will it take to empty or fill the tank completely?
(1) 4 minutes
(2) $3 \frac{1}{3}$ minutes
(3) $2 \frac{1}{3}$ minutes
(4) 2 minutes
(5) 5 minutes
Show Answer
Correct Answer: 101. (2)
Solution: 101. (2) Pipe A can fill the tank completely in $\frac{10 \times 3}{2}=15$ minutes
Clearly, the pipe $\mathrm{B}$ is faster than pipe A. Hence, the tank will be filled.
Part of the tank emptied in 1 minute $=\frac{1}{6}-\frac{1}{15}$
$=\frac{5-2}{30}=\frac{3}{30}$
$=\frac{1}{10}$
$\therefore$ Required time to empty tank wholly $=10$ minutes
$\therefore$ Time taken to empty one third part $=\frac{10}{3}$
$=3 \frac{1}{3}$ minutes
BETA
