Imagine that you have trained your St. Bernard, Bernie, to carry a box of three 8-mm tapes instead of a flask of brandy. (When your disk fills up, you consider that an emergency.) These tapes each contain 7 gigabytes. The dog can travel to your side, wherever you may be, at 18 km/hour. For what range of distances does Bernie have a higher data rate than a transmission line whose data rate (excluding overhead) is 150 Mbps? 

How does your answer change if 

(i) Bernie’s speed is doubled; 

(ii) Each tape capacity is doubled; 

(iii) The data rate of the transmission line is doubled.