## 3 pumps, working 8 hours a day, can empty a tank in 2 days. How many hours a day must 4 pumps work to empty the tank in 1 day?

1. 9
2. 10
3. 11
4. 12

$\therefore$ as per the question,
$\therefore$ n = $\frac{48}{4}$ = 12 hrs.