Answer:
40 boys
Step-by-step explanation:
the ratio at first is 3 girls to 10 boys so you can use multiplication and addition to figure this out.
3 times 4 equals 12
10 x 4 = 40
whatever you multiply on one ratio you do to the other ratio. 40 + 12 = 52
Now the question is asking how many BOYS are there.
there are 40 boys.
