Answer:
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.
[tex]100 - 20 = 80[/tex]%
This is a direct proportion problem. As shown bellow:
504 -> 80%
x    -> 100% Â
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:
[tex]x = \frac{a * b}{c} \\\\x= \frac{504*100}{80} =\frac{50400}{80}=630\\ \\x=630[/tex]