Correct Answer - Option 3 : 90 hrs

**Given:**

A tap can fill a container in 9 hours

With leakage container can be filled in 10 hours

**Concept:**

If a tap can fill a tank in x hours, then the tank filled by the tap in 1 hour = 1/x of the total tank.

**Calculation:**

Part of the container emptied by the leak in 1 hours = (1/9) – (1/10)

⇒ (10 – 9)/90

⇒ 1/90

**∴ ****The required time is 90 hours.**