Question

A Web music store offers two versions of a popular song. The size of the standard version is
2.1
megabytes (MB). The size of the high-quality version is
4.2
MB. Yesterday, there were
1020
downloads of the song, for a total download size of
2982
MB. How many downloads of the high-quality version were there?

Answer 1

Easy. They tell you the standard version is 2.1, the size of quality version is 4.2.
If yesterday there were a total download size of 2982, subtract 1020 from that.

Answer 2

easy for you.. :)

Answer 3

Well... sorry about that, but did you get your answer?

Answer 4

no still figuring out the equation to do it.

Answer 5

Oh, but subtract 2982-1020 and that would be your answer.

Answer 6

1962

Answer 7

Yes.

Answer 8

then how do I figure out how many were high quality?

Answer 9

Just make a linear system, let x be the number of downloads of standard version and y for the high-quality version

Answer 10

Let X be the number of times small file size is downloaded
Let Y be the number of times big file size is downloaded
2.1X+4.2Y=2982
X+Y=1020
Do you agree with that series of equations?

Answer 11

yes I got that part..

Answer 12

now just solve the linear system AMelch8 showed

Answer 13

400

Answer 14

So you are saying Y=400? Let's plug them into the equations and check:
If Y= 400, from the second equation X+Y=1020 therefore X= 620.
Now to check the first equation:
2.1(620)+4.2(400)=2982, this satisfies your two equations.

Good work. It's always a good idea to show your work and then check it after. The good thing about linear algebra is it always gives you a chance to independently check your answer.