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 answer: _________________________________
(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 . _____________________________
