s = standard version amount
h = high quality version amount
we know that there were 1090 downloads of the song, meaning s + h = 1090.
we also know that the total amount of MBs downloaded was 3353 MBs, and since the standard is 2.1 MBs and the high quality is 4.9MBs, then 2.1s + 4.9h = 3353.