. How many downloads of the standard version were there?

Question

A Web music store offers two versions of a popular song. The size of the standard version is 2.3

 megabytes (MB). The size of the high-quality version is 4.6

MB. Yesterday, there were 1290

 downloads of the song, for a total download size of 4692

 MB. How many downloads of the standard version were there? 

Answer 1

x+y = 1290

2.3x + 4.6y = 4692

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y = 1290 - x

23x + 46y = 46920

x + 2y = 2040 <--- divides by 23

x + 2(1290 - x) = 2040

x + 2580 - 2x = 2040

-x = -540

x=540

y = 1290 - 540 = 750