Let's call :
x=the number of downloaded standard version
y= the number of downloaded high-quality version
We have : -the high-quality version was downloaded three times as often as the
standard version => 3x=y
-standard version is 2.8 megabytes .the high-quality version is 4.6
MB.The total size downloaded for the two versions was 4482 MB
=> 2.8x+4.6y=4482
Solve for x,y
x=270 , y=810