Chapter 9.1, Problem 49ES

Black Ice Black ice is a nice covering on roads that is especially difficult to see and therefore extremely dangerous for motorists. The distance a car traveling at $30$ mph will slide after its brakes are applied is related to the outside temperature by the formula $C=\frac{1}{4}D-45$, where $C$ is the Celsius temperature and $D$ is the distance, in feet, that the car will slide. Use this formula for Exercises 48 and 49.

Determine the distance a car will slide on black ice when the outside air temperature is $-3°C$.

How far will a car slide on black ice when the outside air temperature is $-11°C$?