Answer:
B
Step-by-step explanation:
The average rate of change in the closed interval [ a, b ] is
[tex]\frac{f(b)-f(a)}{b-a}[/tex]
Here [ a , b ] = [ 15, 35 ]
and f(b) = f(35) = 400 ← from graph
f(a) = f(15) = 200 ← from graph
Then average rate of change is
[tex]\frac{400-200}{35-15}[/tex] = [tex]\frac{200}{20}[/tex] = 10 m/ s → B
