Answer:
$7.50
Explanation:
4 x 3.00 = $12.00 3.00 off the regular price makes it 12.00 for all the banners
12.00 + 18.00 = 30.00 you add the sale price with the 12.00 to get the total of each banner before the store gave the sale price.
30.00 divide by 4 = 7.50 to find out what the regular price of the banner you divide by the total of banners you bought to get the price of each banner before the sale.