A College Bookstore has been selling one particular tee shirt for a year now. During the Fall term, 100 were sold at a price of $5 each. During the following Spring term, the price was raised to $7; consequently, only 80 were sold.
a) Suppose that the number of tee shirts sold (N) depends linearly on the price charged (x). Write an equation showing this dependence.
Identify and explain the meaning of the slope and the vertical intercept. Then graph the function.
b) According to this relationship, how many tee-shirts would be sold during a term at $3.50 each?