7.1. During a physical education class, all students in the class lined up in a row. It turned out that boys and girls alternated in the row. It is known that exactly $52 \%$ of the students are girls. Find the number of boys in the class. Justify your answer.
Solution: Since there are more than half girls, the first and last student in the row are girls. Let's remove the last girl from the row - there will be an equal number of boys and girls left. In this row, all the boys in the class make up $48 \%$. There are as many girls, another $48 \%$. The remaining $100-2 \cdot 48=4 \%$ corresponds to the removed girl. Thus, one person constitutes $4 \%$, and the number of students in the class is $100: 4=25, 48$ percent of this number is 12 people.

Answer: 12 boys.

Recommendations for checking:

| is in the work | points |
| :--- | :--- |
| Correct and justified answer | 7 points |
| In the correct solution, there is an arithmetic error, possibly leading to an incorrect answer | 6 points |
| Noted that there is one more girl than boys | 1 point |
| Correct answer without any justification | 0 points |

![](https://cdn.mathpix.com/cropped/2024_05_06_3160d2944af22fb50369g-4.jpg?height=476&width=511&top_left_y=1875&top_left_x=133)

To the condition of problem 7.2