Re: Math Formula Question - Need Ideas [message #184523 is a reply to message #184515] |
Sun, 05 January 2014 17:56 |
Allodoxaphobia
Messages: 21 Registered: September 2010
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Junior Member |
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On Sat, 04 Jan 2014 19:33:31 -0500, Richard Damon wrote:
> On 1/4/14, 7:26 PM, Adrienne Boswell wrote:
>> I have a math question to which I can't find the answer. Here is the
>> scenario:
>>
>> Someone goes to a store and has $100.00 worth of items. The merchant
>> gives the customer a 10% discount, so only $90.00 is sent to the bank.
>> Of the original amount, $10.00 goes to the customer for the discount,
>> $80.00 goes to the merchant, $10.00 goes for a processing fee. But those
>> amounts have to be calced on the original amount, not what the bank got.
>> I need a formula to find the original amount if I have the percentage
>> (10%) and the amount the bank got ($90.00). I know in my head that the
>> original amount is $100.00, but I have to do it programatically.
>>
>> I know this is probably dead simple, but I just can't get my head around
>> it.
>>
>> Thanks in advance.
>>
> 10% is 0.1
>
> You got the $90 by multiplying the original $100 by (1-0.1) to get $90,
> so you can divide the $90 by (1 - 0.1) to get the original $100
Then, state and local taxes are usually calc'd on the original price,
not the discounted price.
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