At a certain carnival booth, a trivia game can be played according to the following rule: the player wins 10 gold coins just for participating in the game; he then wins 3 gold coins for each correct answer and loses I gold coin for each wrong answer. At the end of the game when the time is up, the player gains money according to the equivalence: 1 gold coin = $3. If Jad makes 4 mistakes and gains $153 at the end of the game, how many correct answers does he have