In a class of 40 students the number of girls is three fifths of the number of boys. Then find the number of boys in the class.

Correct option is B

Given:

Total number of students = 40

The number of girls is three-fifths of the number of boys.

Solution:
Let the number of boys be B. Then, the number of girls is $$\frac{3}{5}B$$​. The total number of students is the sum of boys and girls.

​$$B + \frac{3}{5}B = 40$$​​

​$$\frac{8}{5}B = 40$$​​

​$$B = \frac{200}{8} = 25$$​​

There are 25 boys in the class.