Final answer:
To find the percentage discount, divide the amount of the discount by the original price and multiply by 100. In this case, the discount is $3 and the original price is $30, so the percentage discount is 10%.
Step-by-step explanation:
To find the percentage discount, divide the amount of the discount by the original price and multiply by 100.
Discount = $30 - $3 = $27
Percentage discount = ($3 / $30) * 100 = 10%.