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 4.7 MB. Yesterday, there were 1400 downloads of the song, for a total download size of 5105 MB. How many downloads of the standard version were there?

Answer 1

Set up the equations:\[2.2x+4.7y=5105\]\[x+y=1400\]Can you solve it from here?

Answer 2

no sorry

Answer 3

Ok...it's two equations with 2 unknowns. Basically take one variable and solve it for the other. The second equation is simpler...so the first step is to solve it for x or y (it doesn't matter). Can you do that part?

Answer 4

(just rearrange it so that x or y = ...)

Answer 5

no dont understand

Answer 6

Ok...let's solve x in terms of y:\[x+y=1400\]\[x=1400-y\] With me so far?

Answer 7

ya

Answer 8

Great. Now just plug that in anywhere you see x in the first equation. The first equation was \[2.2x+4.7y=5105\]Now it becomes: \[2.2(1400-y)+4.7y=5105\]

Answer 9

Now it's possible to solve for y. Once you have y, you can solve for x in the original equations.

Answer 10

im looking for the answer]

Answer 11

for y i got 810

Answer 12

how do you solve for x

Answer 13

810 is correct...you're almost done. Remember that one of the original equations was x+y = 1400. Well, now you have y...just solve for x.

Answer 14

\[x+810=1400\]x=?

Answer 15

x=590

Answer 16

Perfect...you're done. Good luck :)

Answer 17

so is 590 the answer? thank you for your help

Answer 18

x=590, y = 810

Answer 19

yw