Consider the following game. there is a bottle with 20 colored chips inside. there are 2 blue chips, 4 purple chips, 7 green chips, and 7 red chips. you pay $2 and pick one out at random. if you pick a blue chip, you get a prize of $10. if you pick a purple chip, you get a prize of $5. you get nothing for red or green chips. what is the expected value of playing the game?