Answer:
For the first 30 minutes, we will have a line with a given steepness, this will represent the 30 minutes riding at a fast pace.
Then he stops for 20 minutes, we will represent this with a constant line.
Then he again moves for another 30 minutes, but with a slower pace than in the first 30 minutes, then this line will be less steep than the first line.
A sketch of this situation can be seen below.
It is 91 because I know, I know because I know
No because there has to be a remaining opposite persent

the fractions are set up so that each unit cancels out until its only meters/hour
you can multiply all the numerators together to get 72000 and all the denominators to get 1
72000 meters/1 hour
72000 meters in 1 hour
hope this helped
the distance between 16 and -25 is 41