Find the sale price and amount saved after a percentage discount.
A single discount is straightforward: the saving is the original price times the discount rate, and the final price is the original minus that. Where it gets interesting is stacking. Two successive discounts of 20 per cent and 10 per cent are not 30 per cent off. The second applies to the already-reduced price, so the combined effect is 28 per cent — you pay 0.8 x 0.9 = 0.72 of the original. The gap widens as the individual discounts get larger, which is why "extra 10 per cent off sale items" always sounds better than it is.
Order matters in a different way when tax is involved. A discount applied before tax reduces the taxable base and therefore the tax itself; applied after, the tax was already calculated on the full price. Retail practice is normally to discount first and then tax, which favours the buyer, but it is worth checking on large purchases. The other point worth holding onto is that a percentage saving means nothing without the base: 50 per cent off a heavily marked-up item can still be worse value than 10 per cent off a fairly priced one.
No, they make 28 per cent. The second discount applies to the already-reduced price, so you pay 0.8 x 0.9 = 0.72 of the original. Stacked discounts always total less than the sum of their parts.
Before, from the buyer’s point of view, because it reduces the taxable base and therefore the tax charged. Standard retail practice is to discount first and then apply tax, but it is worth confirming on large purchases.
Divide the sale price by one minus the discount as a decimal. An item at 720 after 28 per cent off was 720 divided by 0.72, which is 1,000.
No, because the percentage is applied to different base prices. Half off an inflated price can leave you paying more than a small discount on a fairly priced equivalent. Compare final prices, not the percentages.