6.33 Sunday Shopping When Nova Scotia lifted its Sunday shopping ban, retail stores of all kinds could finally open on Sundays and other holidays, the only exception being Remembrance Day. Nova Scotia was one of the last provinces to place Sunday restrictions on retailers. Suppose that the amount of money spent at shopping centres on Sundays has a normal distribution with a mean of $85 and with a standard deviation of $10. A shopper is randomly selected on a Sunday and asked about his spending patterns.

a. What is the probability that he has spent more than $90 at the mall?

b. What is the probability that he has spent between $90 and $100 at the mall?

c. If two shoppers are randomly selected, what is the probability that both shoppers have spent more than $100 at the mall?