The king receives 64 gold coins in taxes but has reason to b

The king receives 64 gold coins in taxes but has reason to believe that one is counterfeit. He summons you to identify the fake coin. You have a balance that can hold coins on each side. How many times do you need to use the balance to find the lighter, fake coin?

Solution

total 6 times. because first time each side put 32 coins. like that put 16, 8, 4, 2, 1 on each side for identifying fake one.