Question

A family of 17 are trying to get back to their island for Christmas when disaster strikes ¨C their ship hits a rock and will sink in 20 minutes! They have a rescue boat that fits 5 people and can get to the island and back with it in 9 minutes. How many people are able to reach the island without getting wet before the ship sinks?

Answer 1

Time taken by rescue boat to transfer 5 persons to the island and comes back = 9 minutes

Then, time taken by the boat to transfer 10 people to the island and come back will be 18 minutes.

Now, still there are two minutes remaining before the ship sinks. So, the rescue boat can transfer 5 more people to the island. So, this way 15 people can be transferred to the island without getting wet.

So, 15 people can be transferred to the island by the boat before the ship sinks and before getting these people wet.