Student enrollment at a local school is concerning the community because the number of students has dropped to 504 which is a 20% decrease from the previous year. what was the student enrollment the previous year?

The answer is 630 students

Step-by-step explanation:

For this case, we have 504 students and the student enrollment has decrease 20%, which mean 504 is the 80% of the total student enrollment of the previous year.

%

This is a direct proportion problem. As shown bellow:

504 -> 80%

x      -> 100%  

For solving this we use the Mathematical Rule of Three, a method of having three numbers to help calculate the unknown.

b  ->  c

x   ->  a

The algorithm for rule of three is the following: