Answer: Here we got as variables the size of a file and the time needed to download that file. So the size is the independent variable and the time is the dependent variable. (because the time will depend on the size of the file).
A relationship between these two can be of the form:
The time needed to download a file is proportional to the size of the file.
This can be written as : T(w) = A*w
where T is time, w is the weight of the file and A is a proportionality constant.