Based on a survey conducted by Greenfield Online, 25 to 34-year-olds spend the most each week on fast food. The average weekly amount of $44 was reported in a May 2009 USA Today Snapshot. Assuming that weekly fast food expenditures are normally distributed with a standard deviation of $14.50, what is the probability that a 25- to 34-year-old will spend:
a. less than $25 a week on fast food?
b. between $30 and $50 a week on fast food?
c. more than $75 a week on fast food?