8 of the last 40 cars that passed you were black. What is the probability the next car will be black?

Question

8 of the 40 cars are black and the rest are different colors.   

Answer 1

If we assume the last 40 cars that passed are representative of the population of cars on that road, we can estimate that 20% (8 of 40) of all cars on that road are black.  So the probability that the next car will be black is 20%.