The numbers $x^3$ and $y^2$ are inversely proportional. If $x=2$ when $y=15$, what is $y$ if $x=1$ and $y$ is positive? Write your answer in simplest radical form.

In a fruit survey, 300 children choose their favorite fruit out of apples, bananas, and watermelon. 150 chose apples and 90 chose bananas. what percent chose watermelon?