In a class, 3/5 students have brown hair. if 9 students have brown hair, how many students are in the class in total?

9/3 = 3
3 is 1/5 of the total answer
You do 3*5 and that will equal 15

 The answer is:  15 .

There are 15 (fifteen) total students in the class.

(3/5) / 9 =  (2/5) / x ;


Solve for "x" ;  and then add "x + 9" to get the answer;

 (3/5) x  = (2/5)*9 ;

 (3/5) x = (18/5) ;

Multiply BOTH SIDES by "5" ; to get rid of the fraction:

 5* { (3/5) x = (18/5) } ;

  to get: 

        3x = 18 ;

   Divide each side by "3"; to isolate "x" on one side of the equation; and to solve for "x"

        3x / 3 = 18 / 3 ;

    x = 6 ;

  Now add "9" to this number:

  x + 9 = 6 + 9 = 15.

   The answer is:  15 .  

There are 15 (fifteen) total students in the class.

Line the mark up so you will find your answer