Question

Question 25

If 12 pumps can empty a reservoir in 20 hours, then the time required by 45 such pumps to empty the same reservoir is___hours.

Answer 1

$\because$ 12 pumps can empty a reservoir in 20 h.
$\therefore$ 1 pump can empty in $20\times 12$ i.e. 240 h.
Then, 45 pumps can empty the same reservoir in
$\frac{240}{45}h=\frac{240\times 60}{45}min=\frac{14400}{45}=320min=5\times 60+20$
=5h 20 min