Supposedly Einstein solved this problem in three minutes. It might take you longer.
You are given 12 balls and told that one of them has a different weight, whether lighter or heavier.
With three weighings using any scale you are to locate this ball.
Patience is a virtue.
Good luck!
A mathematician named Albert meets a colleague and says: “Nice to see you again John. How is life?”
“I am prosperous, Albert, and happily married with three kids.”
“That’s nice. How old are they?” asked Albert.
“The product of their ages is 36 and the sum is equal to the number of swans you can see in my private lake,” pointing out the window.
Albert thought for a while, then he said. “That’s not enough information, John”
“You are right, I forgot to tell you that the age sum divides that of their squares,” replied John.
Albert thought for a while, smiled and said: “Ok, now I know how old they are, John”
How old are the kids and how many swans are in the private lake?