Puzzle 37 : Chess club

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This puzzle is from popular-mechanics. 

 Amanda lives quite close to her son Mat's school. Every evening she leaves exactly at the same time and travels in her car in a constant speed and picks up Mat after his chess club ends at 5 pm and brings him back at the same constant speed. 

One day, Mat is having a headache and leaves chess club early and starts going home in his portable scooter in their usual route. After he has been scooting for an hour, Amanda meets him on the road, picks him up and they come home together in her car. They reach home 40 minutes earlier than usual.

How much of the chess practice did Mat miss? 

 

Find the solution here.

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