With reference to Exercise 4.58, find the probabilities that the time between successive requests for consulting will be

(a) less than 0.5 week;

(b) more than 3 weeks.

Data From Exercise 4.58

4.58 A consulting engineer receives, on average, 0.7 re- quests per week. If the number of requests follows a Poisson process, find the probability that (a) in a given week, there will be at least 1 request; (b) in a given 4-week period there will be at least 3 requests.