The speed of motor vehicles on a certain stretch of road are normally distributed with a mean of 64.2 mph and a standard deviation of 8.44 mph.

what is the probability that a motor vehicle selected at random is traveling at :

a) more than 65 mph?

b) less than 60 mph?

c) between 65 and 80 mph?

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.