M1 Probability

A fast food shop has 4 delivery motorcycles. The no. of fast food order per hour is a Poisson Distribution. The shop receives k orders in an hour on the average. There are 95% chance there is at least 1 order within an hour.
Find : (a) value of k ( nearest integer).
(b) Probability that there is no delivery motorcycles standby.
(c) Least of no. of delivery motorcycles needed if at least 90% chance of meeting demand in an hour.