How to add percentages

The addition of percentages can be complicated. Let’s say you have a 15% discount and a 30% discount for something you want to buy. What is the total discount that will be applied to your purchase ?. It is not always as simple as adding the same numbers. If you want to add a percentage to another percentage, but you’re not sure how to do it accurately, here’s the help.

First, it is necessary to determine if the percentages will apply both to the base amount, or if they are applied sequentially. For example, let’s say you have an item that costs $20 and you have 15% coupons and a 30% discount. Is a discount of 15% in the first place, the resulting amount is then calculated by 30%?. Or are the discounts applied separately, so that 15% is discounted at $20 and 30% is also discounted at $20?

This is a bit confusing, so let’s see an example. If the discounts are both taken from the basic amount, the math is easy. You just have to add the two percentages and get the total discount. So if a $20 item is discounted 15% and 30%, and both those percentages are taken over the original price of $20, the total discount is 45% discount of $20. 45% of $20 is $9 (20 x 0.45 = 9), which means that the item is discounted $9. Its price is $11.

Now let’s try with sequential discounts. First, let’s say that the $20 item is discounted 15%. 20 x 0.15 = 3, so the discount is $3. The resulting price, then, is $17. Now let’s say that the 30% discount applies to the $17. 17 x 0.3 = 5.1. That discount, then, is $5.10. $17 – $5.10 = $11.90, so the final price of the item is $11.90.


As you can see in this example, adding percentages that apply to the base quantity itself is easier, just add them as if they were regular numbers. Make sure you double check the base amount before you arrive at the addition.

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