An automatic hopper car loader is set to put 75 tons of coal into each car. The actual weights of coal loaded into each car vary according to normal distribution with mean 75 tons and standard deviation 0.8 ton.
A. What is the probability that the average load of 20 cars chosen at random will be less than 74.5 tons?
B. What is the probability that a car chosen at random will have less than 74.5 tons of coal?