3. The sum of two numbers is 135, and $35\%$ of one number is equal to $28\%$ of the other number. Determine these numbers.
Solution. Let one of the numbers be $a$. Then the other is 135-a. According to the condition $\frac{35 a}{100}=\frac{28(135-a)}{100}$. From this, we get $a=60$, so the other number is 75.