62. Hit an ace! Professional tennis player Novak Djokovic hits the ball extremely hard. His first-serve speeds can be modeled by a Normal distribution with mean 112 miles per hour (mph) and standard deviation 5mph. a. How often does Djokovic hit his first serve faster than 120mph ? b. What percent of Djokovic's first serves are slower than 100mph ? c. What proportion of Djokovic's first serves have speeds between 100 and 110 mph?