Answer:

There are 15 girls in the classroom.

Step-by-step explanation:

9:5

Boys: 9

Girls: 5

Total students: 42

9 + 5 = 14

42 ÷ 14 = 3

Boys: 3 × 9 = 27

Girls: 3 × 5 = 15

27 + 15 = 42

Step-by-step explanation:

9+5=14

9÷14×42= 27

5÷14×42= 15

Therefore, there are 15 girls in a classroom.

:))