Problem 4.5. On the meadow, there were 12 cows. The shepherds brought a flock of sheep. There were more sheep than the cows' ears, but fewer than the cows' legs. How many sheep were there if there were 12 times more sheep than shepherds?
Answer: 36 sheep.

Solution. Since there are 12 times more sheep than shepherds, the number of sheep is divisible by 12. In addition, the number of sheep is more than $12 \cdot 2=24$ (the number of ears of cows) and less than $12 \cdot 4=$ 48 (the number of legs of cows). The only number divisible by 12 and between 24 and 48 is 36.