# Math Help - Percentage: given a certain number...

1. ## [Solved]Percentage: given a certain number...

hi there,
in my case i have not to find a +x% starting from a number or -x% from another number but...
given a certain number eg. 124,32 i have to find the original number at which subtracted the 13% , it finally returns 124,32 as result.
How to calculate? Or do you know an online tool just right for this particular case?
Thank you very much

2. ## Re: Percentage: given a certain number...

Originally Posted by johntort
hi there,
in my case i have not to find a +x% starting from a number or -x% from another number but...
given a certain number eg. 124,32 i have to find the original number at which subtracted the 13% , it finally returns 124,32 as result.
How to calculate? Or do you know an online tool just right for this particular case?
Thank you very much
If you have gotten rid of 13% of the original amount, then you have 87% of the original amount remaining. This remaining amount is 124.32

So you need to solve $\displaystyle 0.87x = 124.32$ for $\displaystyle x$, where $\displaystyle x$ is the original amount.

3. ## Re: Percentage: given a certain number...

yes, you're right...thank you