1. Out of four classes, $28\%$ of the students received a "5" for the final math test, "4" - $35\%$, "3" - $25\%$, and "2" - $12\%$. How many students took the test if there are no more than 30 students in each class?
1. Answer: 100.

From the condition, it follows that the number of schoolchildren must be divisible by 25, 20, and 4. The smallest suitable number is 100, the next one is 200, but it would not work for us since, according to the condition, there cannot be more than 120 people in 4 classes.