Answer:
a)
b)

Step-by-step explanation:
The average speed is given by the formula:

The distance covered is 2011.25m , and the time is 122.2s.
Replacing in the formula:

Resulting in a)
.
To get the result in mi/h, do the following conversion:
Knowing : 1 mi = 1603 m and 1 h = 3600 seg