Eight eggs look identical except one is lighter. How can you weigh only 2 times on a balance scale to find out which one is lighter?
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Eight eggs look identical except one is lighter. How can you weigh only 2 times on a balance scale to find out which one is lighter?
One reply on “8 counterfeit coins, a scale, and two weighings”
Weigh coins 1, 2, and 3 against 4, 5, and 6.
If the scale is equal then weigh coins 7 vrs 8. If they are equal then coin 9 is the light one. Otherwise the scale reads the lighter coin between 7 and 8.
If the scale is unequal when weighing coins 1 though 6 then the new problem is to take the three coins on the lighter side of the scale and find which of them is the lighter coin. Re-lable the lighter coins A, B, and C.
Weight A and B. If equal coin C is the light one. If not then the scale reads the light coin.