Answer:
$-2.875 in 1 game
$-287.5 in 100 games
Explanation:
As the probability of getting head in tossing a fair coin is 0.5, the probability of getting 3 heads with 3 coins is 0.5*0.5*0.5 = 0.125
So you have a 0.125 chance of winning and 0.875 chance of losing a game
The expected value for 1 game would be
0.125*5 - 0.875*4 = -2.875
On average you would be losing 2.875 per game. In 100 games you should expect to lose 287.5 dollar