Answer:
3 weeks
Step-by-step explanation:
let the number of weeks be 'x'
The initial price of the bushel = $24
Decrease in price per bushel = $1.50 per week
after x weeks
price of bushel = $24 - 1.50x
Initial yield of bushel = 5
Increase in yield per week = 0.5
after x weeks
yield of bushel = 5 + 0.5x
now,
Return = Price × Number of bushel
or
R = (24 - 1.50x)(5 + 0.5x)
or
R = 120 + 12x - 7.5x - 0.75x²
or
R = 120 + 4.5x - 0.75x²
now,
for point of maxima, differentiating the return with respect to weeks 'x'
we get
R' = 0 + 4.5 - 2(0.75)x = 0
or
⇒ 1.5x = 4.5
or
⇒ x = 3
Hence,
For maximum returns , the oranges should be picked in 3 weeks