Let's start by using algebra to solve this problem.
Let's assume that the total number of students in Ridgewood Junior High School is "x". If 5% of students brought their lunch, then 95% got their lunch in the school cafeteria. We can express this as:
0.95x = number of students who ate in the cafeteria
We also know that 48 students brought their lunch. We can express this as:
0.05x = 48
Solving for x, we get:
0.05x = 48
x = 48 / 0.05
x = 960
Therefore, there are 960 students in Ridgewood Junior High School.