Introduction to Related Rates Practice Test

A cube’s side length $s$ changes over time. If surface area $S=6s^2$, which equation correctly relates $\frac{dS}{dt}$ and $\frac{ds}{dt}$?

A right triangle has legs $x(t)$ and $y(t)$ with hypotenuse $5$. If $x^2+y^2=25$, which differentiated equation is correct?