Final answer:
The probability that the waiting time is less than 8 minutes is 0.2.
Step-by-step explanation:
To find the probability that the waiting time is less than 8 minutes, we need to calculate the area under the probability density function curve up to the value of 8.
Since the waiting time is uniformly distributed between 0 and 20 minutes, the probability density function is a rectangle with base 20 and height 1/20. The area of the rectangle is given by base times height, so the probability is (8/20) x (1/20) = 0.2.