Need help

speed of cars driving along Highway 101 is normally distributed with mean 55 miles per hour and standard deviation 9 miles per hour. The speed limit on Highway 101 is 72 miles per hour an reillance technology measures the speed of all cars so that drivers are fined for speeding. (For calculation purpose, round the z-value to 2 decimal places) a. What is the probability that the next car we observe traveling on Highway 101 is traveling slower than 52 miles per hour? Round your answer to 4 decimal places. b. We randomly observe 15 cars; what is the chance that the combined average speed of these 15 cars is less than 50 miles per hour? c. What proportion of drivers will be fined for speeding? d. In addition to being fined for speeding, drivers driving 10 miles per hour over the speed limit also get their driver's license suspended. Among drivers who are fined, what proportion will lose driving privileges