please solve in a way so that i can understand the difference between Poisson distribution and exponential.

Use the following information to answer the next 3 questions. My wife and I picked up our free NOAA (National Oceanic and Atmospheric Administration) emergency radio several weeks ago. Cars appeared to arrive according to an exponential process every 15 seconds (truth minute). The very gracious start, who had to verify we were Whiteld count residents and provide us with instructions on how to use the radio assigned 250 radios per hour (Following a Poisson distribution). What was the estimated utilization of the gracious staff? How many cars would you expect to see in the "system" (Ls)? Please estimate how long it took for my wife and me expect to wait (in minutes} to receive our radio and leave (We)