Answer:
The farmer should plant 14 additional trees, for maximum yield.
Step-by-step explanation:
Given



So, we have:


Required
The additional trees to be planted for maximum yield
The function is:


Open bracket



Rewrite as:

Differentiate

Equate
to 0 and solve for x to get the maximum of x


Divide by -4

The farmer should plant 14 additional trees, for maximum yield.
Multiply the hours buy her hourly pay:
6 × 40 = 240
6 × 6.5 = 39
6 × 8 = 48
Add them together:
240 + 39 + 48 = 327
ANSWER: Mary Stevens made $327.
I really hope this helped you! c:
According to my calculations the 30% of 570 is 171
10% of 570 is 57
times that by 3 and you get 171