Question

1. a survey found that 3 out of 5 seventh graders have an email account. if there are 315 seventh graders, how many would you expect to have an email account?

Explanation:

Step1: Set up a proportion

Let \(x\) be the number of seventh - graders with an email account. The proportion is \(\frac{3}{5}=\frac{x}{315}\).

Step2: Cross - multiply to solve for \(x\)

Cross - multiplying gives \(5x = 3\times315\). Then \(5x=945\).

Step3: Divide to find \(x\)

Divide both sides by \(5\): \(x=\frac{945}{5}\).

Answer:

\(x = 189\)