Professional tennis player Novak Djokovic hits the ball extremely hard. His first-serve speeds follow an approximately Normal distribution with mean 115 miles per hour and standard deviation 6 mph. Choose one of Djokovic's first serves at random. Let Y= its speed, measured in miles per hour.
(a) Write the event "speed is between 100 and 120 miles per hour" in terms of Y. Then find its probability.
