29. Identify the Lighter Ball There are 9 similar looking balls with the same weight, but 1 among the 9 balls has relatively lesser weight. You are allowed to use a balance twice. How do you identify the ball with lesser weight? Added 9 August 2014 Show Hint Show Solution Hint: Try to divide the balls into groups to minimize the number of comparisons. Solution: 1. Divide the 9 balls into 3 groups of 3 balls each (let's call them Group A, Group B, and Group C).2. Weigh Group A against Group B.3. If one group is lighter, the lighter group contains the lighter ball. If they balance, the lighter ball is in Group C.4. Take the group that contains the lighter ball (3 balls) and weigh 2 of them against each other.5. If one is lighter, that is the lighter ball. If they balance, the remaining ball is the lighter one.
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