IN MR.MAROLE'S CLASS, THREE FOURTH OF THE STUDENTS TAKE MUSIC LESSONS.THAT IS, 15 STUDENTS TAKE MUSIC.HOW MANY STUDENTS ARE IN MR.MAROLE'S CLASS?

Let x = the number of students in the class.

(3/4)x = 15

x = 15 / (3/4)

x = 15 * (4/3)

x = 60/3

x = 20