Assume that the cost per minute of PSTN usage is 15 cents and ten terminals geographically dispersed from a computer center communicate with that center 2 hours per day, 20 days per month. If the monthly cost for connecting a mainframe to the packet network is $$\$ 1000$$ and the cost per hour for packet network transmission is $$\$ 3$$ including packet charges, prepare an analysis of the cost of using the PSTN as opposed to using the packet network. Which method of transmission is more economical? What happens if the number of terminals requiring access to the mainframe increases to 20 ?