You are give 9 identical ball but one ball have different weight from other but looks same . You have to find that ball by using scales.

Question

Accepted Answer

Use scales to weigh groups of balls and narrow down the possibilities until the odd ball out is found.

Divide the balls into groups of three and weigh two groups against each other.
If the scales balance, the odd ball is in the third group. If not, the odd ball is in the heavier group.
Divide the heavier group into three and weigh two groups against each other again.
Repeat until the odd ball is found.
Example: Group 1: 1, 2, 3. Group 2: 4, 5, 6. Group 3: 7, 8, 9. Weigh Group 1 and 2. If they balance, odd ball is in Group 3. If not, odd ball is in heavier group.
Example: Group 1: 1, 2, 3. Group 2: 4, 5, 7. Weigh Group 1 and 2. If they balance, odd ball is 6. If not, odd ball is in heavier group.
Example: Group 1: 4, 5, 6. Group 2: 7, 8, 9. Weigh Group 1 and 2. If they balance, odd ball is 1. If not, odd ball is in heavier group.
Continue dividing and weighing until odd ball is found.

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