Question

Jackson has 50 megabytes (MB) of space left on his smartphone. He can download songs that each use 3.5 MB or videos that each use 7 MB. He wants to download at least 10 new media files. Which pair of inequalities specifies the number of song files, x, and the number of video files, y, that Jackson can download?

Answer 1

Since the amount of media files (amount of song files+amount of video files=x+y) has to be greater than or equal to 10, we have x+y≥10. Next, since each song adds 3.5MB and each video takes 7MB of space, 3.5x+7y is the total amount of MB used and must be, in total, less than or equal to 50 MB, which can be represented as 3.5x+7y≤50. 
x+y≥10.
3.5x+7y≤50