$(25$ pts$.)$

In an auto repair shop, mechanics requiring parts for auto repair present their request forms at the parts department counter. A parts clerk fills a request while the mechanics wait. Mechanics arrive at an average rate of $35$ per hour $($Poisson$).$ A clerk can fill requests in $6$ minutes $($exponential$).$ Suppose that the manager of the parts department decides to have $4$ parts clerks. What is the probability that a new request will have to wait for service? And what is the probability that a new request will have to wait in line less than $5$ minutes?