Problem $18-15($Algo$)$

A manager must determine requirements for waiting space for customers. A priority system is used to process customers, who are assigned to one of two classes when they enter the processing center. The highest$-$priority class has an arrival rate of $3\mathrm{.}4$ per hour; the other class has an arrival rate of $1\mathrm{.}8$ per hour. Both can be described as Poisson$-$distributed. There are two servers, and each can process customers in $15$ minutes, on average. Use Table $18\mathrm{.}4.$

a$.$ What is the system utilization? $($Round your answer to $2$ d