The store sale 85% off only today. Ella planned to buy these skates anyway, and so she bought them immediately.

If she paid $18.00. How much money did she save?

Let x be the original price. Then the discounted price is

discount = x (1 - 0.85)

The discounted price is $18.00. Therefore

18.00 = x (0.15)

x = 18.00 / 0.15

x = $120.00

The amount she saved is $120.00 - $18.00 = $102.00

The answer to this question is that Ella saved $102.00.