Doris the dry cleaner has a single drive$-$thru window for customers. The arrival rate of cars follows a Poisson distribution, while the service time follows an exponential distribution. The average arrival rate is $18$ per hour and she is able to serve each customer in three minutes, on average.

Choose the appropriate spreadsheet template for this problem, update it using the information provided above, and then clearly answer each of the following questions somewhere in the spreadsheet. When you are done, save the file and upload it back here.

What percent of the time is Doris idle?

What is the average number of cars in line?

What is the average time $($in minutes$)$ spent waiting to get to the service window?

What percent of the time are more than $2$ cars at the drive$-$thru window?

Round all answers to $1$ decimal place.