Answer :
For the book store, it is a discreet graph. Every book is a case by itself, no event is dependent on the other. So now variable is dependent on another.
The swimming pool case, the time is the independent variable in the function where the water volume changes with respect to time. So it it has a continuous graph.
Hope this helps.
The swimming pool case, the time is the independent variable in the function where the water volume changes with respect to time. So it it has a continuous graph.
Hope this helps.