A video rental store charges $4 per day to rent a movie and $3 per day 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 twice as many video games as movies, how much did he spend on movie rentals during the summer?

Let the number of movies he rented in summer be x

Let the number of video games he rented in summer be y

Cost of movies per day = $4, so in summer, he spent 4x dollars on movies

Cost of video games per day = $3, so in summer, he spent 3y dollars on video games.

Total money spent by Tony in summer is $140.

So, 140 = 4x + 3y

Now it is given that he rented twice as many video games as movies,

so y=2x

therefore, from the previous equation,

140 = 4x + 3 (2x)

or 140 = 10x

Therefore, x=14 and y = 2 (14) = 28

In summer he spent 4 (28) = $112 on movie rentals