percentage question

Hi I hope someone out there can help me with this!!

I need my worksheet to calculate what VAT has been paid on purchases to help me with my VAT spreadsheet - EXAMPLE:

If I have a bill for £34.70 before VAT and add on 17.5% it gives me £40.77 which is correct, but what i need is a formula/sum that when i put in £40.77 it takes off the correct amount to give me £34.70 (if you know what i mean).
hope i've explained ok and someone can help me with this.
many thanks with anticipation
Julie

PS (I tried taking 17.5% off £40.77 but it dosen't give ther correct amount - which i now understand)

if c2 = ammount paid, and b2 = VAT% (i.e. .175) then you could use this formula to get it.

[code]
=C2/(B2+1)
[/code}

to get 40.77 you are multipying 34.7*1.175, not .175
to solve for 1.175x=40.77 you need to divide both sides by 1.175
then i think you will get the answer you want.

Sorry I 'm not very good at this (useless in fact) is there any way you could show me an example?? if not don't worry i'll keep trying
many thanks

The cells are different than I described, but the formula is in column A. put in the amount actually paid, and the price before VAT will appear in column A.

Tippys your are brilliant - thankyou so much for your help
julie