The average length of movies made in the us between 1994 and 2019 is 110 minutes. the length is approximately normally distributed with standard deviation of 10 minutes. rose and jack have decided to "binge watch 4 movies" during a recent holiday. let xi be the length of movie i, for i = 1, 2, 3 and 4. let x be the sum of the xi. find the following probabilities. a) the probability x is greater than 7 hours. b) the probability x is between 8 and 10 hours. c) the probability x is less than 6 hours.