Problem
The Problem
You have 9 coins, one of which is counterfeit (lighter or heavier — you don't know which). You have a balance scale.
Find the counterfeit coin AND determine whether it's lighter or heavier, using at most 3 weighings.
You have 9 coins, one of which is counterfeit (lighter or heavier — you don't know which). You have a balance scale.
Find the counterfeit coin AND determine whether it's lighter or heavier, using at most 3 weighings.