The first thing you should do in this case is to represent the distance of "the monster Zip line" by a function.
The function for this case is:
D = 120h
Where,
D: distance in kilometers.
h: time in hour.
Substituting the values we have:
D = 120 * (0.25) = 30 Km
answer:
You could travel on the Monster Zip line 30 Km in 0.25 hours