The number of boys in a class is three times the number of girls. Which one of the following numbers cannot represent the total number of children in the class?

The number of boys in a class is three times the number of girls. Which one of the following numbers cannot represent the total number of children in the class?

Explanation
Let the number of girls = x

and

number of boys = 3x.

Then, 3x + x = 4x = total number of students.

Thus, to find the exact value of x, the total number of students must be divisible by 4.