1. During the physical education lesson, all students of grade 8 lined up. It turned out that boys and girls alternated in the line. It is known that exactly $52\%$ of the students in grade 8 are boys. Find the number of girls in grade 8. Don't forget to justify your answer.
Answer: 12. Solution. If there were an even number of students in the row, the number of boys and girls would be equal. But according to the condition, there are more boys. Therefore, the number of students in the row is odd, and boys stand in odd positions. Let there be $n$ girls in the class. Then there are $n+1$ boys, and from the condition, we get that $n+1=0.52(2n+1)$, from which $n=12$.