On average, a customer waits 8 minutes in a queue and the average interarrival time is 4 minutes. What is the average number of customers waiting according to the single-server queue model

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?

Aresearch group wants to find the opinions’ of city residents on the construction of a new downtown parking garage. what is the population of the survey downtown shoppers downtown visitors downtown workers city residents

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.