Answer:
3 and 4 x=25, y=29
Step-by-step explanation:
If you need a step by step explanation, I will edit this later.
Ratio is 5girls:7boys with total 72 students
5+7= 12
72➗12= 6
6(5:7)= 30 girls : 42 boys
New ratio is 3:4 with 48 boys
48➗4= 12
So for girls 3x12= 36
So started with 30 girls ended with 36 girls... 6 girls joined band during the school year.