Answer:
He had $ 40 before bought the game.
Step-by-step explanation:
Let x be the original amount ( in dollars ) contained by Ken,
His spending on game = half of his money = 
So, the remaining money =
= 
Now, his earning = $ 12,
Thus, final amount he has = remaining amount + earning

According to the question,



Hence, he had $ 40 before bought the game .