A company that conducts bus tours found that when the price was $9.00 per person, the average number of customers was 1000 per week. When the company reduced the price to $7.00
per person, the average number of customers increased to 1500 per week. Assuming that the
demand function is linear, what price should be charged to obtain the greatest weekly revenue?
Revenue is price times number sold. Also find this maximum revenue.