Balls in balance
There are nine balls. One is slightly lighter than the rest; the difference is small enough that you can't tell just by picking them up. Using a basic two-sided scale, what's the MINIMUM number of times you'd need to weigh balls to guarantee you find the light one?
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1 solution
The question says MINIMUM no. of times we need to weigh the balls. The answer is 1 because if we put 4 balls on each side and they weigh equal, then the remaining one will be the lighter.