Avideo 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's call x = number of rented movies and y = number of video games rented. We must write a system of equations to find the values "x" and "y". The system that best describes this problem is.4x + 3y = 140.  x = (1/2) * y.  Then we have a system of 2 equations with two unknowns. Resolving it, the values of "x" and "y" are: x = 14 and y = 28. Therefore, Tony rented 14 movies and 28 video games. Finally, Tony spent 14 * 4 = 56 $ on movie rentals.