Answer:
12
Explanation:
because you must add both parts of the ratio together so 5+7=12 which is the total amount of parts. then you divide 48 by 12=4 which is equal to one part. then you multiply 5x4= the number of boys=20 and then 7x4= the number of girls=28 and the difference is 28-20= 8 so there are 8 more girls than boys