Answer:
2
Step-by-step explanation:
The rate of change in the closed interval [ a, b ] is
[tex]\frac{f(b)-f(a)}{b-a}[/tex]
Here [ a, b ] = [ 30, 50 ]
f(b) = f(50) = 100 ← from graph
f(a) = f(30) = 60 ← from graph , thus
average rate of change = [tex]\frac{100-60}{50-30}[/tex] = [tex]\frac{40}{20}[/tex] = 2
