Math problem

[GeoTrail]

I have a problem concerning math, which I'm not very good at.
I'm working on a failry simple calculation for a program.
I have been told that the tax for the ammounts are supposed to be 8% but when I use that the numbers doesn't add up from the papers I have here. I have tried using 7.5476% instead and that seemed to work until I tried that with another entry, then it turned out wrong again. Hopefully someone can help me with this.

Before I add the calculations to the program, I am getting all the calculations done in Excel to make sure they are all correct.

The cells at L and M calculates like this

=K2*0,075476

=G2*0,075476

I've uploaded the spreadsheet to my server if anyone could have a look at it.
It's written in Excel 2002 XP, see the comments in the above mentioned fields for the correct results which should have been displayed.

Download Excel file here: www.geotrail.no/Book1.xls
I'm sorry it's abit messy but hopefully someone understand what I'm trying to do here. If not, please ask.

[Jan Vooijs]

GeoTrail,

Your maths are right is the otherway around. Your 8% is derived from the amount in N if you take 8% from THAT amount you get the amount you wish for in L. Give ore take a round UP or DOWN...

Our dutch tax are done the same there from the LOWER amount going to the HIGER amount!! Yours is the same I think. SO take the 8% tax from the amount in N you get the amount in L add N + L you get K exactly 8%.

See:
3605 * 1.08 = 3893.4 (rounded) 3893 (exactly).

So how to solve this puzzle?? It is:

3893 / 1.08 = 3605

For the other line there is the round error in place see:

2461 / 1.08 = 2278.703704 rounded DOWN is 2278 (exactly)

Have fun with it, but aware for the round up or down error in these cases since every bean counter likes to work with round figures there is a calculus error!!!

Jan V.

[GeoTrail]

Thanks for trying to erxplain Jan.
Let's see if I got it right.
If I do it like this, it should work?:
( AMMOUNT / 1.08 ) * 0.08

Is that what you ment?

[Jan Vooijs]

Thanks for trying to erxplain Jan.
Let's see if I got it right.
If I do it like this, it should work?:
( AMMOUNT / 1.08 ) * 0.08

Is that what you ment?

If you put that formula in L, YES that is correct, but very difficult since you do one devide and one multiplication.

The trick is to calculate the otherway. Not from the high ammount (in K) with the result is L and the answer is N

But from N to L to K.

In K you have your AMMOUNT, in N you have the formula: N/1.08 and in L you have L = K - N, than you have every answer correct.

This helps?? (if not ask)

Jan V.