a player pays $15 to play a game in which a chip is randomly selected from a bag of chips. the bag contains 10 red chips, 4 blue chips, and 6 yellow chips. the player wins $5 if a red chip is selected, $10 if a blue chip is selected, and $20 if a yellow chip is selected. let the random variable x represent the amount won from the selection of the chip, and let the random variable w represent the total amount won, where w=x−15. what is the mean of w ?