In science class, the girl to boy ratio is 3 to 7. If there are 50 students total in the class, how many are boys?

Question

In science class, the girl to boy ratio is 3 to 7.

If there are 50 students total in the class, how many are boys?

Answer 1

Fraction of girls:

3 / (3 + 7) = 3/10

Number of girls:

(3/10)(50) = 15

Fraction of boys:

7 / (3 + 7) = 7/10

Number of boys:

(7/10)(50) = 35

Note the number of girls and the number of boys correctly add up to 50

Answer 2

7/10 of 50 = 35 boys

(7/10)(50) = 7(50/10) = 7(5) = 35