Answer:
There are 6 boys.
Step-by-step explanation:
Given the ratio 3:7. we know that there are 3 boys and 7 girls adding up to a total of 10 parts. If there are 20 children, we simply need to double our ratio to find our answer. The doubled ratio is 6:14, which adds up to 20 children in total and gives us the answer that there are 6 boys.