Question

A video rental company offers a plan that includes a membership fee of $6 and charges $2 for every DVD borrowed. They also offer a second plan, that costs $48 per month for unlimited DVD rentals. If a customer borrows enough DVDs in a month, the two plans cost the same amount. What is that total cost of either plan? How many DVDs is that?

Answer 1

let d be the number of DVD's rented

2d + 6 = 48
2d = 42
d = 21

If the customer borrows less than 21 DVD's the first plan is better
If the customer borrows 21 DVD's s, the cost is the same
If the customer borrows more than 21, the flat rate of $48 is best.