# Given 27 table tennis balls, one is heavier than the others.........

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Given 27 table tennis balls, one is heavier than the others.
What is the minimum number of weighings (using a two-pan balance scale) needed to guarantee identifying the heavy one? Of course, the other 26 balls weigh the same.

posted Nov 12, 2014

3 steps as below. The heavy weight has the heavy ball. In case they are equal, the heavy ball is in the group left on the side.
Step 1. weight 9+9, leave 9 on the side, with the heavier group go to step 2
Step 2. weight 3+3, leave 3 on the side, with the heavier group go to step 3
Step 3. weight 1+1, leave 1 on the side.

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