Brain Teaser Puzzle: If you have a 7-minute hourglass and an 11-minute hourglass, how can you boil an egg in exactly 15 minutes?

If you have a 7-minute hourglass and an 11-minute hourglass, how can you boil an egg in exactly 15 minutes?

Brain teasers are an exciting form of a puzzle that needs thinking to solve. Brain teasers make you think out of the box and exploit your mind's potential. One of the most recent brain teasers trending on social media and boggling many minds is 'If you have a 7-minute hourglass and an 11-minute hourglass, how can you boil an egg in exactly 15 minutes?'. 

One of the challenges associated with this puzzle is that the puzzlers are required to solve this puzzle. So let us first have a look at what this puzzle is.

Image Source: Reddit

If you have a 7-minute hourglass and an 11-minute hourglass, how can you boil an egg in exactly 15 minutes? - Solution

If you are still trying to get the answer to this, we have a hint for you, there are a few different solutions, and all you need to know is basic math to get the equations right. So let us now see the other solutions and then their respective explanations.

Solution

Flip the 7 and 11 simultaneously when the 7 runs out (leaving 4 mins in the 11), then put the egg to boil. Then when the last of those 4mins run out, flip the 11 again, giving you 15 minutes. Now you successfully boiled the egg for exactly 15 minutes.

The picture given below will make you understand this solution better.

Image Source: Reddit