Math
posted by Cliff .
On a math test,12 students earned an A. This number is exactly 25% of the total number of students in the class. How many students are in the class?
'In this problem I'm not sure whether I'm being asked to solve for one or two unknowns. May I have your help ?
Thank you.

only one unknown here, namely the number of students in the class, let that number be x
so
.25x = 12
x = 12/.25 = 48
check: is 1/4 of 48 equal to 12 ?? yes