A country is subject to natural hazards sm.:h as floods, earthquakes. and tornadoes. Suppose earthquakes occur according to a Poisson process with a mean rate of l in IO yr: tornado occurrences are also Poisson-distributed with a mean rate of 0.3 per year. There can be either one or no flood each year: hence the occurrence of a flood each year follows a Bernoulli sequence, and the mean return period of floods is 5 yr. Assume floods, earthquakes, and tornadoes can occur independently. (a) If no hazards occur during a given year, it is referred to as a "good" year. What is the probability of a "good" year?

(b) What is the probability that 2 of the next 5 yr will be good years?

(c) What is the probability of only one incidence of natural hazard in a given year?