Math CentralQuandaries & Queries


Question from GAIL:

what is the formula for calculating percentages to put on top of an items cost.

ie: 115.60 with 15% on top
thank you

Hi Gail,

15% is a fraction. "Per cent" means per one-hundred so 15% = 15/100 = 0.15.

If I built an item for a cost of $115.60 and I want to sell it to you but add 15% of my cost I would charge you $115.60 plus 15% of $115.60 which is

$115.60 + 0.15 × $115.60 = $115.60 + $17.34 = $132.94

I hope this helps,

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