Can you please help me with this problem for my final tomorow?

A game is played by selecting one bill at random from a bag that contains ten $1 bills, five $2 bills, three $5 bills, one $10 bill, and one $100 bill. The player gets to keep the selected bill. There is a $20 charge to play the game.

(a) State the probability distribution for net gains when selecting one bill.

(b) Find the expected value of the probability distribution