Answer:
The slope is 
Step-by-step explanation:
Slope of a dataset:
The slope of a dataset, having two points, is given by the change in y values divided by the change in x values
In this question:
Two points:
x = 0, y = 8
X = 4, y = 13
The slope is:

The slope is 
2x^3+2x^2+5x-7, That would be the answer.
That’s not enough information to say how long he could do it. He could go slower or faster than her but by how much if so. So it’s not enough info.
Mu=80, sigma=39, X=85
Z=(X-mu)/sigma = 5/39=0.128=0.13
P(X<=85)= 0.5517 (from Z-table)
so, P(X>85)=1-0.5517=0.4483 approx. thats 44.8% probability.