Final answer:
After buying a $12.99 movie, Erin has $17.01 left on her gift card. Each song costs $0.99, leading to an inequality of 0.99s ≤ $17.01. Solving this inequality shows Erin can buy a maximum of 17 songs.
Step-by-step explanation:
To find out how many songs Erin can buy with her iTunes gift card, we need to write and solve an inequality. First, we subtract the cost of the movie from the total amount on the gift card.
The movie costs $12.99, so we subtract this from the $30 gift card:
$30.00 - $12.99 = $17.01
This is the amount Erin has left for songs. Each song costs $0.99. Let's use s to represent the number of songs Erin can buy. The inequality representing this situation is:
0.99s ≤ $17.01
To find the maximum number of songs s, we divide both sides of the inequality by $0.99:
s ≤ $17.01 / $0.99
s ≤ 17.18
Since Erin cannot buy a fraction of a song, we round down to the nearest whole number. Therefore, the most songs Erin can buy is 17 songs.