The Parking Attendants Working at the Exit of a Parking $x$

Essay

The parking attendants working at the exit of a parking ramp can process at most 22 cars per minute. If cars arrive randomly at an average rate of $x$ vehicles per minute, then the average wait $W$ in minutes for a car to exit the ramp is approximated by $W(x)=\frac{1}{22-x}$ , where $0 \leq x<22$ .
(a) Evaluate $W(12), W(21)$ , and $W(21.9)$ . Interpret the results.
(b) Graph $W$ using the window $[0,22]$ by $[-.5,1]$ . Identify the vertical asymptote. What happens to $W$ as $x$ approaches 22?
(c) Find $x$ when the wait is 5 minutes.