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Percent and discount

Percent means per hundred. A percentage of an amount is the amount times the percentage divided by 100. A discount is a decrease, so the growth factor is 1 minus the discount as a decimal. The new price is the old price times the growth factor. You can check by calculating how many kroner the discount is, and subtracting them. Percentage points are different from percent, and are treated separately.

p %=p100p\,\% = \frac{p}{100}percent as a decimal
new=old⋅(1−p100)\text{new} = \text{old} \cdot \left(1 - \frac{p}{100}\right)price after a discount

Symbols

ppthe percentage%

Example

25 %=25100=0.2525\,\% = \dfrac{25}{100} = 0.25.

15% of 600 is 600⋅0.15=90600 \cdot 0.15 = 90.

A jacket of 800 NOK with a 30% discount: 800⋅0.70=560800 \cdot 0.70 = 560 NOK.

The new value is the old value times the growth factor.
Practise percentages and growth factors for free →

Several changes in a row →

Part of Mathematics 1P: Percentages and growth factors.