The company "Gasolinas y Aceites SA" works with oil that it unloads from the port and takes to the refinery. The port has 6 unloading docks. When the berths are full, the boats are diverted to holding berths until it is their turn. The boats arrive according to an average of one every 2 hours. To unload the ship it takes an average of 10 hours, following an exponential distribution. The company wants to know the following information


a) How many ships are there on average in the port?

b) How much time, on average, does a ship spend in port?

c) On average, how much time does a ship spend at the waiting dock?

d) What is the probability that upon arrival a ship can be unloaded immediately?