Six coins look identical, but one of them is known to be heavier than the rest. Using a balance scale, what is the least amount number of weighings required to identify the heavy coin?

please help!!! thank you in advance!!!

I think that the answer is 3, but correct me if I'm wrong. 

 Feb 23, 2019

separate the coins into pairs.


weigh one pair against another


if they balance, the 3rd pair has the heavier coin


if they don't balance the heavier pair has the heavier coin


whichever pair it is weigh the two coins against each other to determine the heavier.


2 weighings

 Feb 23, 2019


This is a slight variation on Rom's excellent answer above.


Put three coins on one side of the balance, and three on the other side.

One side will be heavier. 


Take two of the three from the heavier side and put them on the balance. 

If they balance, the odd coin you did not put on the balance is the fake.

If they don't balance, the heavier is the fake. 


Two weighings

 Feb 23, 2019

25 Online Users