Algebra word problem

Question

A Web music store offers two versions of a popular song. The size of the standard version is
2.6
megabytes (MB). The size of the high-quality version is
4.5
MB. Yesterday, the high-quality version was downloaded three times as often as the standard version. The total size downloaded for the two versions was
3542
MB. How many downloads of the standard version were there?

Answer 1

You can write a system of equations to model this situation. Let x = number of standard version songs downloaded and let y = number of high-quality version songs downloaded. Then:

 

2.6x + 4.5y = 3542

3x = y

 

Plug the second equation into the first equation and solve for x:

 

2.6x + 4.5y = 3542

2.6x + 4.5(3x) = 3542

2.6x + 13.5x = 3542

16.1x = 3542

x = 220

 

There were 220 downloads of the standard version.