In a certain very large city, the Department of Transportation (D.O.T.) has organized a complex system of bus transportation. In an advertising campaign, citizens are encouraged to use the new "GO-D.O.T!" system and head for the nearest bus stop to be transported to and from the central city. Suppose that at one of the bus stops the amount of time (in minutes) that a commuter must wait for a bus is a uniformly distributed random variable, T. The values of T run from 5 minutes to 35 minutes.
a: Sketch the probability distribution of T.
b: What is the probability that a random commuter will spend more than 12 minutes waiting for GO-D.O.T?