Friday Brain Teaser - Love in Kleptopia

Posted by Kelly Choo on 19 August 2016

For Friday Brain Teaser, we look at a very sweet puzzle, widely known as Love in Kleptopia.

I know what many of you are thinking - why doesn't Jan just give it to Maria personally? Perhaps, Jan is a little bit busy at the moment. Either way, isn't it romantic, receiving mail the old-fashioned way? Enjoy Friday Brain Teaser everyone!


Friday Brain Teaser Friday's Brain Teaser: Love in Kleptopia


"Jan and Maria have fallen in love (via the internet) and Jan wishes to mail her a ring. Unfortunately, they live in the country of Kleptopia where anything sent through the mail will be stolen unless it is enclosed in a padlocked box. Jan and Maria each have plenty of padlocks, but none to which the other has a key. How can Jan get the ring safely into Maria’s hands?”


This puzzle came from Caroline Calderbank, young daughter of mathematicians Ingrid Daubechies and Robert Calderbank.

Are you ready for the answer? In the solution Caroline had in mind:

Jan sends Maria a box with the ring in it and one of his padlocks on it. Upon receipt Maria affixes her own padlock to box and mails it back with both padlocks on it. When Jan gets it he removes his padlock and sends the box back to Maria; voila!

Did you have fun racking your brains with this puzzle? Click on the banner below to find out other cool ways to keep your mind active!



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