$12.$ Suppose you are to design a LAN for a company that has $100$ employees, each with a desktop computer attached to the LAN. Give the data rate of the LAN for the following typical uses of the LAN:

a$.$ Each employee needs to retrieve a file of average size of $10$ Mbytes in a second. An employee may do this on average $10$ times during the $8-$hour working time.

b$.$ Each employee needs to access the Internet at $250$ kbps$.$ This can happen for $10$ employees simultaneously.