Question

Please help on math equation
I'll post the pic in a bit

Answer 1

think of avg rate of change as the slope
for first 20 minutes look at points (0,200) and (20,119)
what is slope between these 2 points?

then for next 20 min use (20,119) and (40,89)
what is slope between these 2 points?

compare the 2 slopes

Answer 2

how?

Answer 3

slope formula
\[m = \frac{y_2 -y_1}{x_2 -x_1}\]