Answer:
The answer is "[tex]-13.5 \ / minute \\\\[/tex]"
Step-by-step explanation:
The average rate to the changes of pretzels form [tex]t= 1 \ minutes[/tex] to [tex]t=1.5 \ minutes[/tex] will be:
[tex]=\frac{P(1.5)-p(1)}{1.5-1}\\\\=\frac{(20+(1.5)^2- 8 \cos \pi (1.5))-(20+1^2 -8 \cos \pi)}{0.5}\\\\=\frac{22.25-29}{0.5}\\\\=\frac{-675}{50}\\\\=-13.5 \ / minute \\\\[/tex]