There are 24 student and we need to find out 5/8 of the class. So simply it is:
5/8 of 24
First we need to find out 1/8 of 24 so we do
24÷8
Which is: 3
But we want to 5/8 so we do
3×5
Which is: 15
So the amount of girls in Jenny's class is 15.
Hope it helps :)