This scenario is mostly found during a store sale where they offer discounts.
Assuming: Original price = 90 ; discount rate = 25%
Discount value = Original price * discount rate
Discount value = 90 x 25% = 22.50
Since 25% is the discount, you only need to pay 75% of the original price.
Discounted Price = original price * (100-25)% = 90 x 75% = 67.50