Penn State Fleet which operates and manages car rentals for Penn State employees found that the tire lifetime for their vehicles has a mean of 5000 miles and standard deviation of 350 miles. For a random sample of 20 vehicles taken from a normal population what is the probability that the sample mean lifetime of these vehicles is

a)More than 5200 miles?

b)Below 4900 miles?

c)Between 4900 and5200 miles?