Question

An MP3 player costs $70 and song downloads cost $0.85 each. How do you write an expression that represents the cost of the MP3 player and x number of downloaded songs. Then find the total cost if 20 songs are downloaded?

Answer 1

The expression is

`70+0.85n`

For `n=20` this works out to #$87$

Explanation:

The $70 cost of the mp3 player is a fixed expense. We do not need a variable to express it.

The amount spent on music downloads depends on the number of songs we buy, so we use a variable to represent this number, and multiply that variable by the cost of each song.

Add the two terms, and you have the total cost.

Answer 2

See the solution process below:

Explanation:

The expression for the Total Cost of Ownership for this MP3 player is:

`M = p + cx` Where:

`M` is the Total Cost of Ownership for the MP3 player.
`p` is the cost to buy the MP3 player - $70 in this case
`c` is the cost of a CD - $0.85 in this case
`x` is the number of CDs purchased - 20 for the problem we are asked to solve.

Substituting gives:

`M = $70 + ($0.85 xx 20)`

`M = $70 + $17`

`M = $87`