Question

A Web music store offers two versions of a popular song. The size of the standard version is 2.8 megabytes (MB). The size of the high-quality version is 4.9 MB. Yesterday, there were 1070 downloads of the song, for a total download size of 3521 MB. How many downloads of the high-quality version were there?

Answer 1

x=  standard

y = high quality

x +y = 1070

y=1070-x

2.8x + 4.9y =3521

2.8x +4.9(1070-x) = 3521

2.8x+5243-4.9x =3521

-2.1x=-1722

x=-1722/-2.1 = 820

820*2.8 =2296

1070-820 =250

250*4.9 = 1225

1225+2296 = 3521

there were 250 high quality downloads