# math

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The ratio of boys to girls in Mr. Joiner’s class is 5 to 7. If there are 15 boys in the class, how many total students are in the class?

• math -

Let x = the number of girls.
Cross multiply and solve for x.

5/7 = 15/x

Add the number of boys and girls together.

• math -

15 boys is three times the number of boys originally, so there are 21 girls, meaning there is a total of 36 students.

• math -

5+7=12

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