The Blonde Hair Problem


Originally published in the Greek textbook for primary teacher trainees, the Blonde Hair Problem is a very popular mathematical problem. Initially, the problem gives an impression of being an ‘unreal’ mathematical problem with irrelevant information and, hence can’t be solved. But, once you look past through the initial impression and start solving it step by step, it will leave a nice impact on your mathematical experiences.


Here’s how the Problem goes

Two friends Pythagoras and Hypatia, who are very enthusiastic about math, get to meet each other after several years. They have the following conversation.

Pythagoras : Good to see you ! Are you married ? Do you have children ? How old are they ?

Hypatia : Yes, I am married. I have three children and the product of their ages is 36.

Pythagoras : ( after doing some thinking ). I cannot figure out their ages. I don’t have enough clues.

Hypatia : Right ! What if I told you that the sum of their ages is the same as the number of your address.

Pythagoras : ( after doing some more thinking ). I still can’t figure out their ages. I need another hint.

Hypatia : Sure ! My oldest has blond hair.

Pythagoras : Aha ! Now I can, without a doubt , figure out the ages of your children.

What are the ages of Hypatia children ? ( their ages can only be natural numbers )

Does, it look like a real math problem to you. Hmm NO right ! But infact it is and can be solved by following each and every conversation/hint step by step.

So, were you able to find the ages of Hypatia kids ? Leave your answers in the comments below or click the “Show Solution” link below to find out the answer.

I hope you loved the unrealistic nature of ‘The Blonde Hair Problem’ mathematical puzzle. Interested in more resources solving logical thinking puzzles. Check out my picks.

These are great logical and deductive reasoning puzzle books for kids 8 and up. Kids aged 6 would be able to solve some of the puzzle but would need help here and there. Each puzzle is provided with an information and some clues. You need to use the “cross out and circle” technique to find the solution. If your kids love puzzles, these are great to have during long car rides.

If you love activities which are fun and educational for your kids, please consider liking my facebook page MyWorldTheirWay Still, interested in solving more puzzles, check them out here.

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