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Hour Glass

Logic puzzles require you to think. You will have to be logical in your reasoning.

 

Puzzle ID:#29696
Fun:*** (2.93)
Difficulty:** (2.1)
Category:Logic
Submitted By:npf2005*

 

 

 



With a 7-minute hourglass and an 11-minute hourglass, can you explain the quickest way to time a boiling egg for 15 minutes?


Answer

Start both hour glasses as the egg is dropped in the boiling water. When the sand stops running in the 7-minute hourglass, turn it over. When the sand stops running in the 11-minute hourglass, turn the 7-minute hourglass over and leave the 11-minute hourglass. When the sand stops in the 7-minute hourglass, 15 minutes will have elapsed.
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