Final answer:
To find the percent of markup, subtract the cost price from the selling price to get the markup amount, then divide this by the cost price, and multiply by 100. The markup on the t-shirt is about 186%.
Step-by-step explanation:
To calculate the percent of markup on the t-shirt, first determine the amount of markup by subtracting the cost price from the selling price. The cost price is $7 and the selling price is $20, so the markup is $20 - $7 = $13. Markup percent is then calculated by dividing the markup amount by the cost price and multiplying by 100 to get the percentage. Therefore, the markup percentage to the nearest percent is: ($13 / $7) × 100 = 185.71%, which when rounded is approximately 186%.