To find the answer, set 72 equal to a value of (x) multiplied by 0.80, which would be equal to the original value less the 20 percent discount. Divide both sides of the equation by the 0.80 as a way of canceling out the 0.80 coefficient of (x), which leaves a value of (x) equaling $90. The original value of the ring was $90 before the coupon was applied.