Can someone check this for me please..

18 MB of data are to be transmitted over a a megabyte per second connection. How long should the complete transaction take, to the nearest 0.1s.

Size of file / data rate so,
18,874,368 bytes / 4,000,000 = 4.718592 = 4.7 is that correct

a 50 MB file compressed using a ratio of 10 what is the compressed file size

50MB / 10 = 5 MB

Please check for me thanks !

To check if your calculations are correct:

For the first question,
Size of file / data rate:
18 MB / 1 MB/s = 18 seconds

So, the complete transaction should take approximately 18 seconds.

For the second question,
Compressed file size:
50 MB / 10 = 5 MB

So, the compressed file size should be 5 MB.

Your calculations are correct!