Final answer:
Yes, the store marked up the price by 33.33%.
Step-by-step explanation:
To determine if the store marked up the price by 30%, we can calculate the markup percentage using the formula:
Markup Percentage = (Selling Price - Cost Price) / Cost Price * 100%
In this case, the store paid $75 for the clarinet and sold it for $100. Plugging these values into the formula:
Markup Percentage = (100 - 75) / 75 * 100% = 33.33%
Since the markup percentage is 33.33%, which is greater than 30%, the store did mark up the price.