Booker owns 85 video games. he has 3 shelves to put the game on. each shelve can hold 40 video games how many more video games does he have room for?

First lets see how much room there is for holding video games.
There are 3 shelves that can hold 40 video games each, that is:
3*40 = 120
so we can hold 120 video games total.
If now there are 85 video games, how many we can hold still? That is:
120 - 85 = 35
So we still can hold 35 more video games.