3 There are at present 40 solar energy construction firms in the state of Indiana. An average of 20 solar energy construction firms open each year in the state. The average firm stays in business for 10 years. If present trends continue, what is the expected number of solar energy construction firms that will be found in Indiana? If the time between the entries of firms into the industry is exponentially distributed, what is the probability that (in the steady state) there will be more than 300 solar energy firms in business? (Hint: For large l, the Poisson distribution can be approximated by a normal distribution.)