An economist is interested in how the price of a certain item affects its sales. At a price of $p, a quantity, q, of the item is sold. If q = f(p), explain the meaning of each of the following statements: (a) f(150) = 2000 (b) f'(150) = -25

At a price of $p, a quantity, q, of the item is sold.

If q = f(p)

(a) f(150) = 2000 means at price = 150$, the number of items sold is 2000

(b) f'(150) = -25 means rate of sale is negative or the number of items sold will be decreases in future