How do you find our the amount before tax, when all you have is the % and ater-tax amount?

Question

So, if you got charged $500.00 and the amount included 8.1% tax, what is the before tax amount?

Answer 1

Algebraically you have $500 = 108.1%(pretxcost) OR
$500 = 1.081 times pretxcost. Divide each side be 1.081; your answer is: $462.53 (The seller rounded up probably, getting a little more than half a penny, that under
math criteria isn't the way to round... :) )

Answer 2

Quick and easy take the 8.1 % change to a decimal then put a 1 in front of the decimal point like so .081 to 1.081.

Total charge $500 divided by 1.081 = $462.53 pre-tax

to check the figure you can then take the original percentage

8.1% x $462.53 = tax $37.46

now add $462.53 + $37.46 = $499.99

(person rounded up probably to make it even not right but what's a penny now a days :) )

Answer 3

ok...so the final charge was $500...

so the original price multiplied by 1.081 equals $500.
we multiply by 1.081 because it is 1.00 for the entire original price, plus another 8.1% (.081) for the tax.

our equation is:

? x 1.081 = 500

divide both sides by 1.081 to get the ? isolated.

we are left with:

? = 500 divided by 1.081
and so
? = $462.53