Answer:
15/35 or 43% if your going to the nearest whole number so there are 35 boys and 15 girls
Explanation:
Let x = the number of boys
Let 50 - x = the number of girls
Girls/Boys: 3 = 50 - x Cross Multiply
7 x
3x = 350 - 7x
10x = 350
x = 35 boys
50 - x = 15 girls
Check: 15/35 = 3/7