Brain Teasers Optical Illusions Puzzle Hunts Codes & Ciphers Mechanical Puzzles
Personal Links
Browse Teasers
Search Teasers

Perfect Eggs

Math brain teasers require computations to solve.


Puzzle ID:#1403
Fun:*** (2.6)
Difficulty:** (1.92)
Submitted By:gokaran***




For his breakfast, Mr Stone likes an egg that has been boiled for exactly 9 minutes. He has two egg timers (those with sand in them), one that runs for 4 minutes and one that runs for 7 minutes. How can he use these timers to boil his egg?

Open Calculator


Start both egg timers. When the 4 minute timer runs out, turn it over. When the 7 minute timer runs out turn it over. When the 4 minute timer runs out again the 7 minute timer has been running for 1 minute. Turn it over once again. When it stops the egg is done.

What Next?


See another brain teaser just like this one...

Or, just get a random brain teaser

If you become a registered user you can vote on this brain teaser, keep track of
which ones you have seen, and even make your own.


Back to Top

Online Now
8 users and 764 guests

Users In Chat
Follow Braingle!
Fold 'N Fly Paper Airplanes
Easy to follow folding instructions and videos.
Copyright © 1999-2017 | FAQ | Widgets | Links | Green | Subscribe | Contact | Privacy | Conditions | Advertise | Braingle Time: 12:31 am
Sign In Create a free account