math
posted by Max on .
This is a question on a study guide for a test tomorrow. How do you do it? Please help
According to the Federal Highway Administration, teenage males drive an average of 10,718 miles each year. Assume the mileage totals are normally distributed with a standard deviation of 3573 miles. For a randomly selected teenage male, find the probability that he drives less than 9,000 miles in a year.

Z=(meanx)/σ
=(107189000)/3573
=0.4808
From tables, probability for x≤9000
=0.50.184
=0.316