Question

A student has a class that is supposed to end at 9:00AM and another that is supposed to begin at 9:15AM.  Suppose the actual ending time of the 9AM class is normally distributed random variable (X1) with a mean of 9:02 and a standard deviation of 2.5 minutes and that the starting time of the next class is also a normally distributed random variable (X2) with a mean of 9:15 and a standard deviation of 3 minutes.  Suppose also that the time necessary to get from one class to another is also a normally distributed random variable (X3) with a mean of 10 minutes and a standard deviation of 2.5 minutes.  What is the probability that the student makes it to the  second class before the second lecture starts? (Hint: Assume X1, X2 and X3 are independent also think Linear combinations

Answer 1