Assume you are advising a prospective skier. Not being terribly good, he can perform only four pressups without collapsing, and he has taken so far 174 skiing lessons. Not surprisingly, his purpose in seeking a resort is to have fun rather than taking the subject seriously. You can express this in Prolog as follows:
The name of the skier is of course arbitrary, and any name would do as long as you use it consistently.
Enter this information into a file using VED. Then ask Prolog what resort he should go to. Which facts do you think it used to infer the answer?
Now, consider another skier - Charles. Charles has had 10 lessons, his purpose is entirely serious, and he can do 62 pressups in one session. Enter these three facts in such a way that they replace the three you have about Eddie.
Where does Prolog say Charles should go? Which facts would it have used?