Answer:
21 students were in the class.
Step-by-step explanation:
The information in the question tells you that 4/7 of the class is girls.
That means that the remainder of the class is 1 - 4/7 = 3/7 boys
Let the total in the class = x
(3/7)x = 9 Multiply by 7
(3/7)*7*x = 9 * 7 Simplify the right and left
3x = 63 Divide by 3
3x/3 = 63/3
x = 21
There were 21 students in the class.
