Consumers spend an average of $21 per week in cash without being aware of where it goes. (Data extracted from "A Hole in Our Pockets," USA Today, January 18, 2010, p. 1 A.) Assume that the amount of cash spent without being aware of where it goes is normally distributed and that the standard deviation is $5.
a. What is the probability that a randomly selected person will spend more than $25?
b. What is the probability that a randomly selected person will spend between $10 and $20?
c. Between what two values will the middle 95% of the amounts of cash spent fall?