Problem $18-5($Static$)$

A small town with one hospital has two ambulances to supply ambulance service. Requests for ambulances during nonholiday weekends average $0\mathrm{.}45$ per hour and tend to be Poisson$-$distributed. Travel and assistance time averages two hours per call and follows an exponential distribution. Use Table $18\mathrm{.}4.$

a$.$ Find system utilization. $($Round your answer to the nearest whole percent.$)$

b$.$ Find the average number of customers waiting. $($Round your an