People seem to like the brain teasers I’ve posted. Â So here’s another.
I first ran across this when I was about 12 years old. Â I still remember it as one of the toughest brain teasers I ever faced.
It is a very simple problem to explain, but the answer may not be obvious. Â So take your time and think it through.
Find the Counterfeit Coin
You have 12 identical coins. Â One of them is counterfeit. Â The counterfeit coin may be heavier or lighter than the others.
Using a simple balance scale, and in just 3 weighings, identify the counterfeit coin, and determine whether it is lighter or heavier than the others.
Is it possible to solve this problem?
- If “Yes” then what is the solution?
- If “No” then why is it impossible?