Composition of Functions · Exercise 101

The radius $r,$ in inches, of a spherical balloon is related to the volume, $V,$ by $r\left(V\right)=\sqrt[3]{\frac{3V}{4\pi }}.$ Air is pumped into the balloon, so the volume after $t$ seconds is given by $V\left(t\right)=10+20t.$

ⓐFind the composite function $r\left(V\left(t\right)\right).$
ⓑFind the exact time when the radius reaches 10 inches.

Its source prints no answer for this problem, so there's nothing to check against.

OpenStax, Algebra and Trigonometry 2e · §3.4 Composition of Functions · Exercise 101