% after Sebesta book
% speed(chevy,X).
% time(chevy,X).
% distance(chevy,X).
% distance(X,Y).   use ; inbetween to display all

speed(ford,100).
speed(chevy,105).
speed(dodge,95).
speed(volvo,80).
time(ford,20).
time(chevy,21).
time(dodge,24).
time(volvo,24).
distance(X,Y) :- speed(X,Speed),
                 time(X,Time),
                 Y is Speed * Time.