Word Problem

Question

The table represents the total cost an online store charges for streaming movies. It charges an annual membership fee and a fee for each movie streamed.
Movies Streamed 0       1        2       3
Total Cost ($)    58.00 61.00 64.00 67.00

 

A local rental store uses the function C = 4.50m to determine how much to charge for movie rentals. C is the total cost and m is the number of movies rented. The store does not charge customers a membership fee. If 45 movies are rented in a year, which option is cheaper?
[A] Streaming movies from the online store is less expensive for 45 movies in a year.
[B] Renting DVDs from the neighborhood store is less expensive for 45 movies in a year.
[C] Both options cost the same amount for 45 movies in a year

Answer 1

The online store charges according to the linear function

  C(m) = 58 + 3m

 

Notice the price increases by $3 per movie, hence the slope of M=3 appears in bold in the above linear function.

 

So C(45) = 58 + 45*3 = 58 + 135 = $190

 

The rental store charges C(45) = 4.50*45 = 202.50

 

The online store is cheaper by $12.50 for 45 videos