7. In a class where the number of girls is 36% of the total number, there are 48 boys. How many students are there in the class?

This problem involves the very basic formula of representing the total by a variable N. The number of boys plus the number of girls is equal to N but the number of girls is 36% of N.

Writing the representations

N = number of boys + number of girls

N = 48 + 36% of N

N = 0.36N + 48

N - 0.36N = 48

0.64N = 48

N = 48 / 0.64

N = 75

There are 75 people in the class. The number of boys is 48 and the number of girls is 27. The percentage of girls is 36% of 75.