Chapter 5, Problem 50PS

Write a function called parkingcharge that, given the type of vehicle (c for car, b for bus, t for truck) and the hours a vehicle spent in the parking lot, returns the parking charge based on the rates shown below.

$\begin{array}{|l|}\hline \text{car \$2 per hour}\hfill \\ \text{bus \$3 per hour}\hfill \\ \text{truck \$4 per hour}\hfill \\ \hline\end{array}$