x 50 0 40 30 20 10 Games of Chance Find the expected winnings for the games of chance described in Exercises 17-20. (See Example 5.) 17. In one form of roulette, you bet $1 on "even." If one of the 18 positive even numbers comes up, you get your dollar back, plus another one. If one of the 20 other numbers (18 odd, 0, and 00) 66 comes up, you lose your dollar. 18. Repeat Exercise 17 if there are only 19 noneven numbers (no 00). 19. Numbers is a game in which you bet $1 on any three-digit num- ber from 000 to 999. If your number comes up, you get $500. 20. In one form of the game Keno, the house has a pot contain- ing 80 balls, each marked with a different number from 1 to 80. You buy a ticket for $1 and mark one of the 80 numbers on it. The house then selects 20 numbers at random. If your number is among the 20, you get $3.20 (for a net winning of $2.20). 21. Online Gambling An online gambling site offers a first prize of $50,000 and two second prizes of $10,000 each for registered users when they place a bet. A random bet will be selected over a 24-hour period. Two million bets are received in the contest. Find the expected winnings if you can place one registered bet of $1 in the given period. 22. Online Gambling An online gambling site offers a loutery with a first prize of $25,000, a second prize of $10,000, and a third prize of $5000. It takes $5 to enter and a winner is selected at random. What are the expected winnings if 20,000 people enter the lottery?