Answer:
The oranges should be picked in 2 weeks for maximum return
Step-by-step explanation:
We assume that the return of the owner is y ($)
Assume that the number of weeks the oranges should be picked to have maximum return is x (weeks). (x≥0)
If collect now, the price for each bushel is $27
As the price per bushel decrease by $1.50 per bushel each week
=> After x weeks, the price of a bushel decrease: 1.5x ($)
=> The price of 1 bushel after x weeks is: 27 - 1.5x ($)
If collect now, each tree can yield 7 bushels
As the yield increases by half a bushel per week for the next 5 weeks
=> After x weeks with x ≤ 5, each trees would yields: 7 + 0.5x (bushels)
The return = The price of each bushes × The quantity of bushels
=>

⇔

⇔

We have: if the equation has the form of
with a≠0, its maximum value is:

In the equation
, we have: a = -0.75; b = 3; c = 189
=>

To look for the number of weeks, we should find x (0≤x≤5) with which y = 192

⇔

⇔

⇔

⇔

⇔

⇔ x = 2
The oranges should be picked in 2 weeks for maximum return