If nine users are connected to a wireless network that offers a maximum data rate of 54 Mbit/s and a throughput of 45%, what is the typical average practical message data rate available for each user?

A student is trying to download a file from the internet, which has the size of 100 MB and is using internet of download speed of 600 Kbps. 

How long does it take to download the file by the student, express your answer in seconds and minutes? 

The students decided to compress the files before storing it to CD. He need to compress the file to 40 MB file, what is the compression ratio? 

If student (A) starts copying his compressed file to CD with writing speed of 980 Kbps: 

How much time needed to finish copying his compressed file (40 MB), express your answer in seconds and minutes? 

How much time needed to finish copying his original file (uncompressed file) to CD, express your answer in seconds, minutes?