Alcohol risk

The 2009 Youth Risk Behavior Survey found that about 5 out of 12 high school students drank some alcohol in the 30 days preceding the survey. If a high school has 2400 students, how many would be expected to have used alcohol within 30 days?

Correct answer:

x =  1000

Step-by-step explanation:

$$\begin{gathered} r=\frac{5}{12}\doteq 0.4167 \\ x=r\cdot 2400=\frac{5}{12}\cdot 2400=\frac{5\cdot 2400}{12}=\frac{12000}{12}=1000 \end{gathered}$$

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