To find the profit as a percentage:
profit as a percent = (price sold - purchase price) / (purchase price)
profit as a percent = (5.25 - 2.50 ) / (2.50)
profit as a percent = 2.75 / 2.50
profit as a percent = 1.1
then we will multiply 1.1 by 100 to get a percentage
profit as a percent = 110%