Gloria has a lunch account in the school cafeteria. the balance, f(x), in her account can be represented by the function f(x) = –1.50x + 40, where x is the number of meals purchased. suppose –1.50 changed to –2.75. what does this mean in the context of the problem?

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?