# The variables x and y vary inversely, when x is 9 y is 36 if x is 3 what is y?

Jun 29, 2015

When $x = 3$, $y = 108$.

#### Explanation:

We know that

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

$k = x y$

If $x = 9$ and $y = 36$,

k = 9 × 36 = 324. So

$y = \frac{324}{x}$

If $x = 3$,

$y = \frac{324}{3} = 108$