Excel geekery question

[muthafunka]

Of all places...sorry but you know, where else can I ask such crap?

I'm trying to do a formula in Excel (I'm slowly sucking less at Excel but it's an ongoing process) and need to get this nailed down asap.

I'm making an invoice and 10.21% tax will be deducted. If I want to end up with $100 in my hand, how much do I have to bill for and how do I write this formula?

That's it...I hang my sorry head...

[Galt]

x*(1-0.1021)=100
x*0.8979=100
x=100/0.8979
x=111.37


Hence,
- formula: 100/0.8979
- bill for: 111.37

[muthafunka]

Fantastiche!! Made my night in many ways and yes I can see what you did there!
One caveat, I must also make sure to round down to the nearest whole number and still get the exact $100..... well 1000 yen innit.

Thanks again

ps that's going to be my new avatar here and there for a while if you don't mind

[H20nly]

it's extra awesome cuz it's... <- Mr. Wong

[beats me]

[scott nathaniel]

@ Galt & Mutha:
Put down the math and stick with the meth!

[Quiggers]

press Alt+F11

[Machinesworking]

@ Galt & Mutha:
Put down the math and stick with the meth!

Seriously!
If you want a $100 profit and you have a 10.21% sales tax or whatever, you already have your answer.

100*1.1021= $110.21

Serious case of over thinking or trolling here.

[Galt]

@ Machines.

Try again, this is not how maths works. Your figures produce a result of $98.96.

Tell us all again how you run your own business

[scott nathaniel]

@ Galt & Mutha:
Put down the math and stick with the meth!

Seriously!
If you want a $100 profit and you have a 10.21% sales tax or whatever, you already have your answer.

100*1.1021= $110.21

Serious case of over thinking or trolling here.

He's actually correct, but meth makes the math quicker. Work it backwards:

a - (a * .1021) = 100.00
111.37 - (111.37 * .1021) = rounded up = 100.00

[muthafunka]

aren't you just adding 10.21% there to give me 110.21% of the original?

what I need is the 100% total before tax, so that when you take take 10.21% off that you're left with exactly $100 ie 89.79%=$100

[scott nathaniel]

aren't you just adding 10.21% there to give me 110.21% of the original?

what I need is the 100% total before tax, so that when you take take 10.21% off that you're left with exactly $100 ie 89.79%=$100

If you want a hundred friggin dollars remaining at your specified tax rate, then Galt gave you your formula. Trust me, go with it, you'll have exaclty one benji to 'blow.'

[Machinesworking]

aren't you just adding 10.21% there to give me 110.21% of the original?

what I need is the 100% total before tax, so that when you take take 10.21% off that you're left with exactly $100 ie 89.79%=$100

This is where the over thinking comes in. You're wanting to charge someone $100 for your work and not have the sales tax make it less than $100.
So, you will pay the government $10.21 for every $100 you make. You're not 'making' $110.21, you're collecting the tax on the sale from the client, and handing it over to the state.

The only reason I could see wanting to do it the other way is if you didn't want the customer to know that them paying the sales tax was part of the sale?

[scott nathaniel]

aren't you just adding 10.21% there to give me 110.21% of the original?

what I need is the 100% total before tax, so that when you take take 10.21% off that you're left with exactly $100 ie 89.79%=$100

This is where the over thinking comes in. You're wanting to charge someone $100 for your work and not have the sales tax make it less than $100.
So, you will pay the government $10.21 for every $100 you make. You're not 'making' $110.21, you're collecting the tax on the sale from the client, and handing it over to the state.

The only reason I could see wanting to do it the other way is if you didn't want the customer to know that them paying the sales tax was part of the sale?

This is the formula for percentage deduction:

A - (A * %) = R

You are using the amount he wants as a remainder (R) in place of the amount (A). The 100.00 is the desired result and A is the variable we are trying to calculate. You are starting the equation with A already determined and that has messed up your math.

[muthafunka]

aren't you just adding 10.21% there to give me 110.21% of the original?

what I need is the 100% total before tax, so that when you take take 10.21% off that you're left with exactly $100 ie 89.79%=$100

If you want a hundred friggin dollars remaining at your specified tax rate, then Galt gave you your formula. Trust me, go with it, you'll have exaclty one benji to 'blow.'

My answer came in late, I was replying to Machinesworking.

Muchos gracias one and all.