What would the answer to this be?

show working out i want to check if what i did was correct.

STEPS:

1) set up an equation. use x as a variable
       
      2x + 3x = 25

2) solve the equation for x:

      5x = 25
      x = 5

3) Now that you know the value of x, substitute it into the expression for how any girls there are, which is "3x" (since the ratio of BOYS to GIRLS is 2:3):

      3x
      = 3(5)
      = 15

So 15 is your answer, and there are 15 girls in the class.

Total is 25
boys : girls
2 : 3
2+3=5
25/5=5
5*3=15
15 boys