Answer:
First, remember the relation:
Distance = Speed*Time.
We know that the distance is 120mi.
A) For the biker we know that:
Time = 8hours.
Speed = Distance/Time = 120mi/8h = 15 mi/h.
B) For the bus we know that:
Time = 2 hours.
Speed = Distance/Time = 120mi/2h = 60 mi/h.
C) For the truck we know that:
Time = 2.5 hours.
Speed = Distance/Time = 120mi/2.5h = 48 mi/h.
D) For the rider on a horse we know that:
Time = 18.75 hours.
Speed = Distance/Time = 120mi/18.75h = 6.4 mi/h.
E) The equation for the speed is:
Speed = Distance/Time.
You can see that time is in the denominator, this means that if for a fixed distance, the time increases, then the denominator increases, which would imply that the speed decreases.
Then the speed is inversely proportional to the time when the distance is fixed.
