Posted by Angie on .
Define variables and write a system of equations for this situation. Solve using substitution.
Suppose you want to join a video store. Big Video offers a special discount card that costs $9.99 for one year. With the discount card, each video rental costs $2.49. A discount card from Main Street Video costs $20.49 for one year. With the Main Street Video discount card, each video rental costs $1.79. After how many video rentals is the cost the same?
Cost of x videos from Big Video:
9.99 + 2.49x
Cost of x videos from Main Street Video:
20.49 + 1.79x
Set the two equations equal to each other to find when the cost will be the same:
9.99 + 2.49x = 20.49 + 1.79x
10.5 = .7x
x = 15 videos