Introduction to Related Rates Practice Test

A rectangle has perimeter $P=2x+2y$; if $\dfrac{dP}{dt}=0$, and $\dfrac{dx}{dt}=3$, what must $\dfrac{dy}{dt}$ be?

A cylindrical candle has radius $2$ cm and height $10$ cm; if height decreases at $0.3$ cm/hr, how fast is volume changing?