Question

Suppose that y varies inversely with x. Use the information to find k, and then choose the equation of variation. x = 13 when y = 100.

Answer 1

To solve this problem you must apply the proccedure shown below:

1. You have that $y$ varies inversely with $x$ and when $x=13$ the value of $y$ is $y=100$.

2. Therefore, you can write the following expression, where $k$ is the constant of proportionality:

$y=\frac{k}{x}$

3. Solve for the constant of proportionality and substitute the values to calculate it:

$k=yx\\ k=(100)(13=\\ k=1300$

4. The equation is:

$y=\frac{1300}{x}$

The answer is: $k=1300\\ y=\frac{1300}{x}$