Island crossing

It’s summer and four friends go to visit an island for the day. The four friends are late for dinner, so we need to help them get back quickly!

The four friends must all get back to the mainland on one little rowing boat. They’re all on the island at the end of the day.

The rowing boat carries two people maximum at any time.

It is quite dark in the evening and they have just one lamp. When they are travelling, they must carry a lamp to see the way.

A pair must row together at the rate of the slower friend as they are sharing the lamp.

  • Belle takes 1 minute to row across
  • Hugo takes 2 minutes to row across
  • Zara takes 7 minutes to row across
  • George takes 10 minutes to row across

 

Scroll down for the answer!

 

 

Answer

The fastest solution takes 17 minutes for all of the friends to get back to the mainland.

The second fastest solution takes 21 minutes for all of the friends to get back to the mainland.