Ellen is downloading a file. After 2 minutes, there are 38.4 megabytes left to download. After 8 minutes, there is only 9.6 megabytes left to download. What is the size, in megabytes, of the file.?

find the average download rate.
(38.4 - 9.6) / (2-8) = -4.8 mb/min

that means in the first 2 min she had downloaded 2(4.8)  = 9.6 mb

38.4 mb left + 9.6 mb already downloaded = 48 mb total