Answer:
627.8 MB
Explanation:
Let's say R = Ruben's download, and M = Tariq's download.
R + M = 951.8 MB
We know that R is equal to 324 MB, so we can remove that from the total.
M = 951.8 - 324
M = 627.8 MB
That means Tariq downloaded 627.8 MB of music.
Hope this helps!