15% of the students in mrs. madison’s math classes have an ‘a’. if 18 students have an ‘a’, how many students are in mrs. madison’s math classes? [type your answer as a number.]

120 .

Explanation: 

15% of x = 18 ;  x = total number of students.

Solve for: "x" ; which is our answer.


15 % of x = (15/100) * x = (0.15)x ;
 

(0.15) x = 18 ; 

Divide each side by: "(0.15)" ; to isolate "x" on one side of the equation; and to solve for "x" , which is our


(0.15)x / (0.15) = 18 /(0.15) ;
 
   x = 120 ;  They are 120 students in Mrs. Madison's math classes.

The question asks to type the answer as a number. So:

120 .