Assuming the cost of playing the game is the same as the two dollars lost (you can't lose more than $2 on a game):
To calculate expected value, multiply each probability by its payout or loss, and add the numbers together:
Game A) 0.10
Game B) 2.05
Game C) 1.00
Since the question is a bit unclear, let's also look at expected value is she has to pay $2 to play, but can also lose an additional $2:
Game A) -1.90
Game B) 0.05
Game C) -1.00
I believe it is the first one, but you may want to clarify with the teacher or a fellow student.
b) If Tanya decides to play a game, she will choose Game B) because this has the highest expected value.
