air Flight ticket

An airline sells 120 tickets for a flight that seats 100. Each ticket is non-refundable and costs $200. The unit cost of flying a passenger (fuel, food, etc.) is $80. If the flight is overbooked, each person who does not find a seat is given $300 in cash. Assume it is equally likely that any number of people between 91 and 120 show up for the flight. Rounded to the nearest thousand (e.g., 18500 rounds to 19000), on the average how much expected profit (ignoring fixed cost) will the flight generate?