Solution to: Crazy Cows
The neighbor borrowed an extra cow, to make the total number of cows 18. Then the oldest son got 1⁄2 of 18 is 9 cows, the middle son got 1⁄3 of 18 is 6 cows, and the youngest son got 1⁄9 of 18 is 2 cows. Since 9+6+2 = 17, the cows could be divided among the three brothers in such a way that the borrowed cow was left over and could be returned to its owner.
Back to the puzzle