$29.99 is the final price. "y" is the original price. Subtract the savings from the original price to get the final price of $29.99. 70% = 70/100 = .70 y - (y x .70) = 29.99 y - .7y = 29.99 .3y = 29.99 .3y/.3 = 29.99/.3 y = 99.96667 y = $99.97 (rounded)