A video rental store charges $4 to rent a movie and $3 to rent a video game. During one summer, Tony paid a total of $140 to rent movies and video games from this store. If he rented 7 more video games than movies, how much did he spend on movie rentals during the summer?

Let's make the number of movie rentals "x" and the amount of video game rentals x+7 and if movies cost $4 and video games costs $3, then the equation would be:
                                 4x + 3(x+7) = 140
                                              ↓
                                 4x + 3x + 21 = 140
                                              ↓
                                   7x + 21 = 140
                                              ↓
                                         7x=119
                                              ↓
                                           x=17

So the number of movie rentals would be 17 and you multiply it by 4 and you will get 68.

The answer is A. $68