86. A student has a class that is supposed to end at 9:00 AM and another that is supposed to begin at 9:10 AM Suppose the actual ending time of the 9 A.M. class is a normally distributed rv X, with mean 9:02 and standard deviation 15 min and that the starting time of the next class is also a normally distributed rv X, with mean 9.10 and standard deviation 1 min. Suppose also that the time necessary to get from one classroom to the other is a normally distributed rv X, with mean 6 min and standard deviation I min. What is the probability that the student makes it to the second class before the lecture starts? (Assume independence of X, X, and X, which is reason- able if the student pays no attention to the finishing time