Self-Test 4

Querying with the route/2 procedure
 
You are advised to complete your solution before you look at the answer.
 
  Using the route/2 and path/2 procedures, which of the following queries are true and to what would the variables be instantiated?
 
1.
route(a, 1).
2.
route(1, 5).
3.
route(3, b).
4. route(9, 5).
   
 

With the following queries, type a semi-colon (";") after each reply from Prolog until you get the "no" response: eg

     | ?- route(7, End).

     End = b ? ;

     End = 8 ? ;

     End = b ? ;

     no
5.
route(4, End).
6.
route(Start, 5).