Answer:
28 students
Explanation:
The easiest way to solve this would be to set up an equation.
We can start by naming x the number of students in Reggie's class.
Therefore, our equation would be:
0.75x=21
We can get this by knowing 75% of the students brought their lunches, and there were 21 students that did.
75% is equivalent to 75/100 which is 0.75.
Next, we can solve the equation.
0.75x=21
To do this, we have to isolate x.
We need to reverse the multiplication with division.
We can do this by dividing both sides by 0.75 (What you do to one side you must do to the other)
0.75x/0.75=21/0.75
x=28
This means that there are 28 students in the class.