sorry one more expected value problem

ugh this is proving very difficult for me...

A box contains two gold balls and three silver balls. You are allowed to choose successively balls from the box at random. You win 1 dollar each time you draw a silver ball. After a draw, the ball is not replaced. Show that, if you draw until you are ahead by 1 dollar or until there are no more gold balls, this is a favorable game?

Side question - what determines whether a game is favorable or not?

thank you very much!