If you would like to write and solve a system of equations that represent the situation above, you can do this using the following steps:
s ... number of songs
m ... number of movies
$55.00 = $1.25 * s + $2.75 * m
55 = 1.25 * s + 2.75 * m
26 songs and movies = s + m
26 = s + m
s = 26 - m
55 = 1.25 * s + 2.75 * m
55 = 1.25 * (26 - m) + 2.75 * m
55 = 1.25 * 26 - 1.25 * m + 2.75 * m
55 - 32.5 = 1.5 * m
22.5 = 1.5 * m
m = 22.5 / 1.5 = 15 movies
s = 26 - m = 26 - 15 = 11 songs
The correct result would be 15 movies and 11 songs.
