Find the indicated probabilities using the geometric distribution or Poisson distribution. Then determine if the events are unusual. If convenient, use Poisson a probability table or technology to find the probabilities.
Assume the probability that you will make a sale on any given telephone call is 0.18. find the probability that you (a) make your first sale on the fifth call, (b) make your sale on the first, second, or third call, and (c) do not make a sale on the first three calls.