A recent report in USA today indicates a typical family of four spends $490 per month on food. Assume the distribution of food expenditures for a family of four follows the normal distribution, with a standard deviation of 90 month.
A. What percent of the families spend more than $30 but less than $490 per month on food?
B. What percent of the families spend less than $430 per month on food?
C. What percent spend between $430 and $600 per month on food?
D. What percent spend between $500 and $600 per month on food?