5.96 A management consultant found that the amount of time per day spent by executives performing tasks that could be done equally well by subordinates followed a normal distribution with a mean of 2.4 hours.

It was also found that 10% of executives spent over 3.5 hours per day on tasks of this type. For a random sample of 400 executives, find the probability that more than 80 spend more than 3 hours per day on tasks of this type.