According to the Air Transport Association of America, the average operating cost of an MD-80 jet airliner is $2,087 per hour. Suppose the operating costs of an MD-80 jet airliner are normally distributed with a standard deviation of $176 per hour.

(Round the value of z to 2 decimal places. Round your answers to 2 decimal places.)

(a) At what operating cost would only 20% of the operating costs be less?