BrainteasersFamous For 15 Minutes
An eccentric professor used a unique way to measure time for a test lasting 15 minutes
He used just two hourglasses. One measured 7 minutes and the other 11 minutes.
During the whole time he turned the hourglasses only 3 times (turning both hourglasses at once counts as one flip). How did he measure the 15 minutes?
![](https://www.datocms-assets.com/34817/1701709288-screenshot-2023-12-04-at-17-01-17.png)
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