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 $169 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 23% of the operating costs be less? $

(b) At what operating cost would 65% of the operating costs be more? $

(c) What operating cost would be more than 85% of operating costs?