Word Problem

Question

A Web music store offers two versions of a popular song. The size of the standard version is
2.2
megabytes (MB). The size of the high-quality version is
4.2
MB. Yesterday, there were
820
downloads of the song, for a total download size of
2844
MB. How many downloads of the standard version were there?

Answer 1

Let's say           x = the number of standard downloads

Then       820 - x  = the number of high-quality downloads

 

The amount of data downloaded for the standard downloads is

 

2.2x

 

The amount of data downloaded for the high quality downloads is

 

4.2(820 - x)

 

If we add these expressions we get the total amount of data downloaded, so

 

2.2x + 4.2(820 - x) = 2844

 

Simplifying, we get

 

2.2x + 3444 - 4.2x = 2844

 

-2x +3444 = 2844

 

-2x = -600

 

x = 300.

 

So there were 300 standard downloads.