High School Math : Understanding Indirect Proportionality

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #244 : Algebra Ii

If \(\displaystyle y\) is inversely proportional to \(\displaystyle x\), and if \(\displaystyle x=2\) when \(\displaystyle y=8\), find a formula for \(\displaystyle y\)

Possible Answers:

\(\displaystyle y=\frac{16}{x}\)

\(\displaystyle y=4x\)

\(\displaystyle y=\frac{x}{16}\)

\(\displaystyle \frac{16}{y}=x\)

\(\displaystyle y=16x\)

Correct answer:

\(\displaystyle y=\frac{16}{x}\)

Explanation:

Since y is inversely porportional to x, you can use the standard equations of \(\displaystyle y=\frac{k}{x}\) where k is a constant. Plugging the given x and y into this equation to solve for k, \(\displaystyle k=16\). To get the answer, substitute k into the standard equation. 

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