A certain company sends 40% of its overnight mail parcels via express mail service E1. Of these parcels, 2% arrive after the guaranteed delivery time (denote the event late delivery by L). If a record of an overnight mailing is randomly selected from the company s le, what is the probability that the par- cel went via E1 and was late?
96. Refer to Exercise 95. Suppose that 50% of the overnight parcels are sent via express mail service E2 and the remaining 10% are sent via E3. Of those sent via E2, only 1% arrive late, whereas 5% of the parcels handled by E3 arrive late.
a. What is the probability that a randomly selected
parcel arrived late?
b. If a randomly selected parcel has arrived on time, what is the probability that it was not sent via E1?