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 4.9 MB. Yesterday, there were 770 downloads of the song, for a total download size of 2345 MB. How many downloads of the high-quality version were there?

Answer 1

(2345-2.1s)/4.9=h

Answer 2

You need to do a system of equations:

770=h+s
and
2.1s+4.9h=2345

Answer 3

standard=s, HQ=h s+h=770, 2.1s+4.9h=2345

Answer 4

from there?

Answer 5

i can substitute into the first equation?

Answer 6

now solve for a variable, like i did above.
"(2345-2.1s)/4.9=h"
substitute this for h into the other equation so you have
770=h+s
now:
770= [(2345-2.1s)/4.9]+s

Answer 7

yes

Answer 8

to find s then substitute s into the second equation?

Answer 9

once you have h you can substitute it into either. For this one the
"770=h+s"
would be a lot less messy

Answer 10

ok thanks

Answer 11

working...

Answer 12

My suggestion is the elimination method. Multiply the first equation by -2.1
You have -2.1s - 2.1h=-1617.
Add the two equations together.
2.8h=728
divide both sides by 2.8
h=260... Now just substitute 260 for h in the first equation and solve for s.

Answer 13

just need the HQ # ^^)