Question

A farmer is tracking the amount of corn his land is yielding each year. He finds that the function f(x) = −x2 + 20x + 50 models the crops in pounds per acre over x years. Find and interpret the average rate of change from year 1 to year 10.
The crop yield increased by 9 pounds per acre from year 1 to year 10.
The crop yield decreased by 0.09 pounds per acre from year 1 to year 10.
The crop yield decreased by 11 pounds per acre from year 1 to year 10.
The crop yield increased by 99 pounds per acre from year 1 to year 10.

Answer 1

Answer:

The crop yield increased by 9 pounds per acre from year 1 to year 10.

Step-by-step explanation:

To solve this we are using the average rate of change formula: $Av=\frac{f(x_2)-f(x_1)}{x_2-x_1}$, where:

$x_2$ is the second point in the function

$x_1$ is the first point in the function

$f(x_2)$ is the function evaluated at the second point

$f(x_1)$ is the function evaluated at the first point

We know that the first point is 1 year and the second point is 10 years, so $x_1=1$ and $x_2=10$. Replacing values:

$Av=\frac{-(10)^2+20(10)+50-[-(1)^2+20(1)+50]}{10-1}$

$Av=\frac{-100+200+50-[-1+20+50]}{9}$

$Av=\frac{150-[69]}{9}$

$Av=\frac{150-69}{9}$

$Av=\frac{81}{9}$

$Av=9$

Since $f(x)$ represents the number of pounds per acre and $x$ the number of years, we can conclude that the crop yield increased by 9 pounds per acre from year 1 to year 10.