A Dog Named Bernie (carries 3 8-mm tapes, each containing 7 gigs; dog runs at 18 kph)

mario99

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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.


I understand this type of problems very well. But here I am confused because I don't know how to relate the dog to me. I mean that I know I am the owner of the dog but what is the relationship between me and him when he carries 8-mm tapes? To answer (i), (ii), and (iii), I have first to answer the main problem. It has given me speed and asking me to find the distances, but the time is also missing. I have two unknowns.
 
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.


I understand this type of problems very well. But here I am confused because I don't know how to relate the dog to me. I mean that I know I am the owner of the dog but what is the relationship between me and him when he carries 8-mm tapes? To answer (i), (ii), and (iii), I have first to answer the main problem. It has given me speed and asking me to find the distances, but the time is also missing. I have two unknowns.
I think the important "given condition" is:

The dog can carry a box of three 8-mm tapes and travel to your side, wherever you may be, at 18 km/hour.​
Sounds like the maximum speed of transfer is 18 km/hr (you are a fast runner - marathon-olympians run at ~23 km/hr)
 
I think the important "given condition" is:

The dog can carry a box of three 8-mm tapes and travel to your side, wherever you may be, at 18 km/hour.​
Sounds like the maximum speed of transfer is 18 km/hr (you are a fast runner - marathon-olympians run at ~23 km/hr)
Thank you khansaheb


I get it. The speed of the dog is the speed of data transfer.

This problem can be solved by a simple formula if we have one unknown, but we do have two.

[imath]\displaystyle \text{speed} = \frac{\text{distance}}{\text{time}} = 18[/imath]

The given information:
(a) [imath]\displaystyle 8-\text{mm tapes}[/imath]
(b) [imath]\displaystyle 7 \ \text{gigabytes}[/imath]

(a) is a thickness and (b) is a bandwidth. None of them either time nor distance.
 
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