Question

The ratio of boys to girls in a class is 5:7. There are 36 students in the class. How many students are boys?

Answer 1

Answer:

5x = 7y

x + y = 36

x = 36 - y

180 - 5y = 7y

180 = 12y

12y = 180

y = 180 / 12

y = 90 / 6

y = 30 / 2

y = 15

x = 36 - 15

x = 21

hope it helps

Answer 2

Answer:

G = 21, B = 15

Step-by-step explanation:

$\frac{b}{g} = \frac{5}{7} \\ b = \frac{5g}{7} \\ given \: b + g = 36 \\ \frac{5g}{7} + g = 36 \\ \frac{5g + 7g}{7} = 36 \\ 12g = 7 \times 36 \\ g = \frac{7 \times 36}{12} \\ g = 21 \\ b + g = 36 \\ b + 21 = 36 \\ b = 36 - 21 \\ b = 15$