Final answer:
The percentage increase of the coffee mug's price from $6.24 to $8.77 is approximately (c) 40.32%, which does not match any of the provided answer options exactly.
Step-by-step explanation:
To calculate the percentage increase in the price of the coffee mug, we need to first determine the difference in price and then divide that by the original price.
The price was marked up from $6.24 to $8.77, so the increase is $8.77 - $6.24 = $2.53.
Next, we divide this increase by the original price to find the percentage: ($2.53 / $6.24) × 100 = approximately 40.32%.