CU Denver requires faculty and staff to check in each day when on campus to ensure they are healthy. Each person must present their completed health survey certificate at a check$-$in desk and they then receive a color$-$coded wristband that allows them to be on campus for that day only. Between $8$AM and $10$AM$,$ the average arrival rate to the check$-$in desk at the business school building is $30$ people$/$hour$.$ It takes $90$ seconds, on average, to complete the check in process.

$-$ What is the probability of having no customers in the line? $($provide at least three decimals$)$