Final answer:
The merchant's percentage loss was calculated by finding the loss per dozen, which is $0.50, and then applying the percentage loss formula, resulting in a 16.67% loss.
Step-by-step explanation:
The student is asking about a situation where a merchant experiences a percentage loss by buying sweets at a higher price and selling them for a lower price. To calculate the percentage loss, we first find the loss per dozen by subtracting the selling price from the cost price. Here, the loss per dozen is $3.00 - $2.50 = $0.50. The percentage loss can then be calculated using the formula:
Percentage Loss = (Loss per dozen / Cost price per dozen) x 100%
In this case, the percentage loss equals ($0.50 / $3.00) x 100% which equals approximately 16.67%.