Question

An online music is charging $25 for 100 downloads and an additional $1.50 for every download over 100. Write an equation that could be used to determine the total cost, c, for downloading , d, number of songs over 100.​

Answer 1

`c=25+1.5d`

Explanation:

Let c represent the total cost and d represent the number of downloaded songs over 100. Therefore, the corresponding equation is:

`$c=25+1.5d$`

For example, if we downloaded 150 songs, we would expect the cost to be $25 plus $1.50 each for 50 songs: $25 + ($1.50 × 50) = $25 + $75 = $100.

We can verify by substituting 50 for d in our equation:

`c=25+1.5d\\c=25+1.5(50)\\c=25+75\\c=100`