Answer
number of trees $n = 50$
maximum yield of apples $A(n)= 22500$
Work Step by Step
Calculate the maximum of the function by substituting the values from the function into $n_{MAX}=\frac{-b}{2a}\rightarrow n_{MAX}=50$ which is the number of trees planted.
Then substitute $n=50$ into the function to get the maximum yield of apples.
