Question 1:

If you win 10% of the time, then you win once out of every ten games.
In ten games, you pay ten dollars and win four, so you lose six dollars every ten games.
If you know how many games you are playing, you can divide that number by ten and multiply the result by six.
But uh, for each game individually, the most you lose is one dollar, as that is the price of the game. I think the biggest question here is what exactly is being asked of you.