Question

The ratio of boys to girls in Ella’s grade is 3 to 4. The ratio of boys to girls in Minh’s grade is 4 to 5. Each grade has a total of 20 girls.

How many boys are in each grade?

There are boys in Ella’s grade and boys in Minh’s grade.

Answer 1

There are 15 boys in Ella’s grade and 16 boys in Minh’s grade.

Explanation:

What is a ratio?

A ratio has two or more numbers that symbolize relation to each other. Ratios are used to compare numbers, and you can compare them using division.

If the ratio of boys to girls in Ella's grade is 3: 4, and there are 20 girls, we can use this equation to solve for the number of boys:

• 3 × 5 = 15

Why do we multiply by 5?

Well, good question! We multiply by 5 because in order to go from 4 to 20, we multiply the 4 by 5.

If the ratio of boys to girls in Minh's grade is 4: 5 and there are 20 girls, we can use this equation to solve for the number of boys:

• 4 × 4 = 16

Why do we multiply by 4?

Like above, we multiply by 4 because in order to go from 5 to 20, we multiply the 5 by 4.

Therefore, there are 15 boys in Ella’s grade and 16 boys in Minh’s grade.