The number of animals caught in an animal trap during an hour has the Poisson distribution with parameter ????. If it is known that the probability that no animal is trapped during an hour equals e−2.5, find

(i) the expected number of trapped animals during an hour;

(ii) the probability that at least three animals are trapped;

(iii) the probability that at least three animals are trapped in an hour, if we know that at least one has been trapped.