A ship 45kms away from the nearest port develops a leak and water seaps into the ship at the rate of 5 tonnes every 20 minutes. When 30 tonnes of water gets into the ship the ship will sink. However, the ship's pump can throw out water at the rate of 5 tonnes an hour. What should be the minimum speed at which the ship should sail so that it reaches the port safely?
Permited time to reach to port is 3 HRs. (bcoz every hour 10tonnes water get into the ship)
So speed must be > 15km/hr