Trucks arrive at a distribution centre at a rate of 18 per hour following a Poisson distribution. On average a work crew can unload 6 trucks per hour. Crew cost is $400 per hour and the cost to have a truck waiting is $450 per hour. What is the average number of trucks waiting to be unloaded? Multiple Choice eBook O 0.227 O 1.233 O 0.856 O 0.354 O 0.468