Twenty percent of the cars passing through a school zone are exceeding the speed limit by more

Question:

Twenty percent of the cars passing through a school zone are exceeding the speed limit by more than 10 mph.
a. Using the Poisson formula, find the probability that in a random sample of 100 cars passing through this school zone, exactly 25 will exceed the speed limit by more than 10 mph.
b. Using the Poisson probabilities table, find the probability that the number of cars exceeding the speed limit by more than 10 mph in a random sample of 100 cars passing through this school zone is
i. At most 8
ii. 15 to 20
iii. At least 30