A ship 75 kms from the port springs a leak that admits 3 tonnes of water every 10 minutes. 45 tonnes of water will cause the ship to sink. However, the pumps in the ship can throw out 3 tonnes of water every hour. What should be speed of the ship if she were to reach shore safely?

Correct Answer: 3 hours

The leak admits water at the rate of 3 tonnes every 10 minutes = 3×6

= 18 tonnes every hour.

The pumps throw out water at the rate of 3 tonnes every hour.

Therefore, net water that gets into the ship = 18 – 3 = 15 tonnes every hour. ‘

45 tonnes of water will sink the ship.

Therefore, the ship has got 45/15 = 3 hours before it will sink.

The port is 75 kms away. Hence the ship should cover 75 kms in 3 hours i.e at the rate of 25 km/hr.
Hence , 3 hrs