The taxi and takeoff time for commercial jets is a random variable x with a mean of 8.7 minutes and a standard deviation of 2.9 minutes. assume that the distribution of taxi and takeoff times is approximately normal. you may assume that the jets are lined up on a runway so that one taxies and takes off immediately after the other, and that they take off one at a time on a given runway. what is the probability that for 33 jets on a given runway, total taxi and takeoff time will be less than 320 minutes?