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View Full Version : k... dumb math question.....



devilmaster
10-26-07, 12:08 PM
I'm racking my brain to figger this out, and i'm having no luck.

here's my dilemma, its a restaurant thing and this is just a basic example....

on a $7.90 bill, you add 16% for tax, which I just mulitiply by 1.16 to find the tax of 1.264 and to get a final total of $9.164, rounded down to $9.16....

So this is my prob... at the end of the night, I want to quickly find the tax charged based on the final total of $9.16...

what do I multiply/divide 9.16 by to find the tax?

It's probably something really simple that i'm missing....

Thx in advance...

Don Quixote
10-26-07, 12:26 PM
I think it is calculated as .16/1.16 * 9.16 = $1.26
It may be different for those now valuable Canadian dollars. :gomer:

devilmaster
10-26-07, 12:32 PM
I think it is calculated as .16/1.16 * 9.16 = $1.26
It may be different for those now valuable Canadian dollars. :gomer:

That does work, but I don't think its what I need cause it doesn't work for different tax percentages......

The 16% is a harmonized tax, but if I were to split the tax into the 6% GST and 10% PST, .1/1.1 * 9.16 = .83 when 10% tax on 7.90 is 79 cents.

Don Quixote
10-26-07, 12:36 PM
It's then .10/1.16 * 9.16 = .79
and .06/1.16 * 9.16 = .47
.79 + .47 = 1.26

devilmaster
10-26-07, 12:37 PM
It's then .10/1.16 * 9.16 = .79
and .06/1.16 * 9.16 = .47
.79 + .47 = 1.26

cool! owe ya a beer. :) Thanx!

Sean Malone
10-26-07, 12:50 PM
Damn 'new' math. If it was 'old' math I woulda been able to help. :)

Warlock!
10-26-07, 01:22 PM
Or look at it this way...

$9.16
*divided by*
116 (which is the total number of percentage units that make up the total bill of $9.16)
*times*
16 (the percentage of the bill which is tax)
*equals*
$1.26 (rounded down)

Don Quixote
10-26-07, 01:35 PM
We are proably being complicit in Steve's cheating on his income taxes. Great.

devilmaster
10-26-07, 01:35 PM
Or look at it this way...

$9.16
*divided by*
116 (which is the total number of percentage units that make up the total bill of $9.16)
*times*
16 (the percentage of the bill which is tax)
*equals*
$1.26 (rounded down)

oh great. now its two beers. :irked: ;)

Thanx also :)

Methanolandbrats
10-26-07, 01:46 PM
A $7.90 tab? I did'nt know you had to tip at McDonalds.

TKGAngel
10-26-07, 01:50 PM
If you know your tax percentage is 16% you could just take your final total of $9.16, multiply by .84 and then subtract that number from the $9.16 total.

Andrew Longman
10-26-07, 02:12 PM
16% sales tax? That's more than twice the NJ sales tax. Wow. You better get healthcare with that. :D

Gnam
10-26-07, 02:28 PM
It's then .10/1.16 * 9.16 = .79
and .06/1.16 * 9.16 = .47
.79 + .47 = 1.26

Don Quixote's method is best. But I might write it a little bit differently.

(1) devilmaster knows his final price is 9.16

he also knows the original bill is equal to the final price divided by the total tax rate:
(2) 9.16/1.16 =7.90
and he knows 10% of 7.90 is .79:
(3) .10*7.90 = .79

but he doesn't want to go back and sum all the orginal bills, just the receipts.

Now he may not know or care what the original bill was, but since he already knows that the original bill is equal to the final price divided by the total tax rate:
(2) 7.90 = 9.16/1.16,
he can rewrite equation (3) as:
(4) .10*(9.16/1.16) = .79

This way he can determine the individual tax owed as long as he knows the final price, the total tax rate, and the individual tax rate.

devilmaster
10-26-07, 02:32 PM
A $7.90 tab? I did'nt know you had to tip at McDonalds.

Pbbbbt. ;) http://myspace.com/terracottapizza


If you know your tax percentage is 16% you could just take your final total of $9.16, multiply by .84 and then subtract that number from the $9.16 total.

That's where the disconnect is. I thought that too at first, but your math is wrong - whether you multiply 16% or 84% of 9.16, that formula taxes the tax. if you multiply any tax number on the 9.16, you are taxing the tax cause the 9.16 total includes the tax. Tax. I just like saying Tax. Tax, tax, tax. (that's for you, WB :) )


16% sales tax? That's more than twice the NJ sales tax. Wow. You better get healthcare with that. :D

6% Goods and Services Tax - Federal, 10% provincial sales tax on alcohol. 8% provincial sales tax on everything else.

Thats why its so confusing - I need to quickly find the taxes on a bill at the end of the night. (small restaurant, no POS)

Let's take the problem a step further - 2 glasses of wine come to 7.90, with 16% tax it comes to $9.16. That 9.16 will be added to the food bill which was a margherita pizza. 6.50, plus 14% tax for the food, so 7.41. add 7.41 to 9.16, total 16.57. so thanks to the extra 2 percent tax on booze, I have that do those extra couple steps of math to ensure I account for that 2 percent properly and we remit it to the govt.

So thanks guys, you helped me out immeasurably. :thumbup:

WickerBill
10-26-07, 02:39 PM
SMOCK!

devilmaster
10-26-07, 02:52 PM
SMOCK!

WHAT ON EARTH IS WRONG WITH YOU?!?

;)

ferrarigod
10-26-07, 03:20 PM
what grade are you in dm?

devilmaster
10-26-07, 03:27 PM
what grade are you in dm?

I couldn't be edupacated at 30 different colleges like you - but it makes it easier for me to cheer on a single team though. Don't have to jump onto a lot of bandwagons.

Wabbit
10-26-07, 05:34 PM
16% sales tax? That's more than twice the NJ sales tax. Wow. You better get healthcare with that. :D

If the measure passes, after the first of the year, Seattle will have a 9.8% sales tax :eek:

SteveH
10-26-07, 05:57 PM
Chicago might be 11% soon. :shakeshead:

TKGAngel
10-26-07, 06:19 PM
That's where the disconnect is. I thought that too at first, but your math is wrong - whether you multiply 16% or 84% of 9.16, that formula taxes the tax. if you multiply any tax number on the 9.16, you are taxing the tax cause the 9.16 total includes the tax. Tax. I just like saying Tax. Tax, tax, tax. (that's for you, WB :) )

I was just thinking that the goofy math was because of the rounding up to the 9.16.

At least this question had nothing to do with two trains leaving Points A and B and where they would meet (the answer is always "with a big bang in Missouri.")

extramundane
10-26-07, 07:44 PM
If the measure passes, after the first of the year, Seattle will have a 9.8% sales tax :eek:

Thanks to some shady operating by our city government, a meal out (and certain prepared foods from the grocery store) here come with an 11% tax heaped on top. :irked:

nissan gtp
10-26-07, 08:42 PM
just estimate and round up

and order another beer while you thing about it

Sean O'Gorman
10-26-07, 09:23 PM
Chicago might be 11% soon. :shakeshead:

Don't look at it a 11%, look at it as 3.66% per vote.

devilmaster
10-27-07, 01:24 AM
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