Final answer:
The farmer should sell his apples on the 7th day to maximize his income.The correct answer is option A.
Step-by-step explanation:
To determine when the farmer should sell his apples to maximize his income, we need to calculate the revenue and costs for each day.
Let's start with the revenue:
- On the 1st day, the farmer can sell 200 crates at $120 per crate, so the total revenue is $24,000.
- On the 2nd day, the farmer can sell 210 crates at $116 per crate (since the price dropped by $4), so the total revenue is $24,360.
- Continuing this pattern, we find that on the 7th day, the total revenue is $24,840.
- On the 8th day, the price would have dropped to $80 per crate and the farmer can sell 220 crates, resulting in a total revenue of $17,600.
- On the 9th day, the total revenue is $17,040.
- On the 10th day, the total revenue is $16,480.
Now, let's calculate the costs:
- On any given day, the farmer incurs no additional costs for harvesting the apples.
- Therefore, the costs remain constant at $0 per day.
To calculate the income, we need to subtract the costs from the revenue. From the calculations, we can see that the income is highest on the 7th day ($24,840), so the farmer should sell his apples on the 7th day to maximize his income.