The Bureau of Labor Statistics gathers data about a variety of subjects. One of them is the Consumer Expenditures Survey. From this survey we learn that the mean annual expenditure of an American family on dairy products is $450. For the following questions, assume that the expenditure is normally distributed with a standard deviation of $80.

a. What is the probability that a family spends more than $600 per year on dairy products?

b. What is the amount above which only 10% of the population spend?