What is the answer to in a science class the girl to boy ratio is 3 to 7 out of 50 student how many are boys?

If the ratio of girls to boys is 3:7,

then: 3/10 of the class are girls and 7/10 of the class is boys

Note: 3+7 = 10

If the class has a total of 50 students we can find the number of boys by doing this:

(total number of kids) x (fraction of the kids that are boys) = # of boys

50 x (7/10) = 35

There are 35 boys in the class.