Suppose 40% of the vehicles passing through a toll booth are trucks and the rest are cars.
A truck pays a $5 toll whereas a car pays $3.
(a) Find the expected revenue from the next vehicle that passes through.
(b) Find the expected revenue from the next 10 vehicles.
(c) Find the variance of the revenue from the next vehicle that passes through. What units are attached to this variance?
(d) Find the variance of the revenue from the next 10 vehicles. Assume whether each vehicle is a car or truck has nothing to do with the type of any other vehicle.