It costs $12 to play a game. There is a probability of $$\frac14$$ of winning $40 and a probability of $$\frac38$$ of winning $25. Calculate the financial expectation of this game.
P(lose) = $$1-\frac14-\frac38=\frac38$$
E = $$\frac14\times\,$40+\frac38\times\,$25-\frac38\times\,$10-$12$$ (don’t forget to subtract the cost of playing the game)
∴ E = $3.63