1. A toll bridge charges $10.25 for passenger cars and $15.75 for other vehicles. Suppose that 60% of all vehicles are passenger cars. If 25 vehicles cross the bridge during a particular daytime period, (a) What is the probability that at least 3 of them are passenger cars? (b) What is the expected revenue and its associated standard deviation? (Hint: Note that the revenue is a linear function of the number of passenger cars.)