Two Strings

You have two strings, and some matches. Each string will burn in exactly 1 hour. You need to use the strings to measure 45 minutes.

The difficulty is that the strings do not burn at a constant rate. They have thin and thick parts and you cannot predict how long any piece of the string will take to burn. So you cannot light the string in the middle or cut the string and be able to predict how long it will take to burn.

 

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