Answer:
If boys to girls, 5:8. If girls to boys, 8:5.
Explanation:
There are 8 girls and 5 boys. That means the ratio could be 8:5 or 5:8. You didn't specify in the question which one, so I can't tell you which one. But, if the question asks for boys to girls, put 5:8. If it asks for girls to boys, but 8:5.