Calculation type: Applying two successive percentage discounts to the same item (discount stacking).
Watch out: Two discounts of 20% and 10% are NOT the same as one single 30% discount, because the second cut comes off the already-reduced price. The real total discount is only
28%.
Formula explanation:
Final price = Price × (1 − First discount / 100) × (1 − Second discount / 100)
Final price = $200 × (1 − 20 / 100) ×
(1 − 10 / 100) = $200 × 0.8 × 0.9 = $144
After the first 20% discount, the price is $200 × 0.8 = $160. The extra 10% then comes off $160, not the original $200.
Effective discount = (1 − Final price / Price) × 100 = (1 − 144
/ 200) × 100
= 28%