# Y varies directly as the cube root of x. Y is 30 when x is 1, how do you find y when x is 27?

Jan 25, 2017

$Y = 90$ when $x = 27$

#### Explanation:

We are told the Y varies directly as the cube root of x

Thus $Y = k \sqrt[3]{x}$ For some $k \in \mathbb{Q}$

We are also told that $Y = 30$ when $x = 1$

$\therefore 30 = k \sqrt[3]{1} \to k = 30$

Hence: $Y = 30 \sqrt[3]{27}$ when $x = 27$

$Y = 30 \times 3 = 90$