During a 10-year period, sharks killed an average of 6.4 people each year worldwide. Find the probability that the number of people killed by sharks next year is

(a) exactly three,

(b) more than six, and

(c) at most five.

In Exercises 21–26, find the indicated probabilities using the geometric distribution, the Poisson distribution, or the binomial distribution. Then determine whether the events are unusual. If convenient, use a table or technology to find the probabilities.