Final answer:
The fruit vendor made a profit of $150 per pineapple, which is 50% of the cost price.
Step-by-step explanation:
In order to determine whether the fruit vendor made a profit or loss, we need to compare the cost price with the selling price. The vendor buys pineapples in boxes of 60 for $18,000, which means the cost price per pineapple is $18,000/60 = $300. He sells them at $5,400 per dozen, which means the selling price per pineapple is $5,400/12 = $450.
Profit or loss = Selling price - Cost price = $450 - $300 = $150
So the fruit vendor made a profit of $150 per pineapple.
To calculate the profit or loss as a percentage of the cost price, we use the formula:
Profit or loss percentage = (Profit or loss / Cost price) x 100
Profit or loss percentage = ($150 / $300) x 100 = 50%