Hi Anna,
File size = 2.5 GB = 2500 MB
Rate of upload = 5.25 MB/s
Total time given for uploads = 48 hours = 48*60 = 2880 minutes = 2880*60 = 172800 seconds
2500MB / 5.25MB/s = 476.19 seconds to upload one client file
172800 seconds / 475.19 seconds/client file = 362.88 files
The maximum number of files the firm can upload in a weekend, is 362 files. The .88 represents the 363rd file. The upload on that file will begin but will not be completed in the 48 hours given.