A bus company has adopted the following pricing policy for groups that wish to charter its buses. Groups containing no more than 40 people will be charged a fixed amount of $2,400 (40 times $60). In groups containing between 40 and 80 people, everyone will pay $60 minus 50 cents for each person in excess of 40. The company’s lowest fare of $40 per person will be offered to groups that have 80 members or more. Express the bus company’s revenue as a function of the size of the group. Draw the graph.