Answer is in the photo. I can only upload it to a file hosting service. link below!
tinyurl.com/wpazsebu
36 girls
step-by-step explanation:
the 48 boys is 4 parts of the ratio
divide 48 by 4 to obtain one part of the ratio
= 12 ← 1 part of the ratio
3 parts = 3 × 12 = 36 ← number of girls