Question

A Web music store offers two versions of a popular song. The size of the standard version is
2.5
megabytes (MB). The size of the high-quality version is
4.5
MB. Yesterday, the high-quality version was downloaded four times as often as the standard version. The total size downloaded for the two versions was
5740
MB. How many downloads of the standard version were there?

Answer 1

Let s be standard and h be high-quality versions of the song.
To figure this out, let's make a system of equations: 
2.5s + 4.5h = 5740
h = 4s
First substitute the second equation into the first for h.
2.5s + 18s =5740
Then combine like terms.
20.5s = 5740
Lastly, divide each side by 20.5 to get the number of standard downloads: 
s = 280
Hope this helps!