Im trying to create an exspenses account sheet that self calculates tax.
Cells are E10 TAX y/n , G10 Gross, I10 total tax
I need to-
Create a drop down menu for cell E10 offering three options,
None,
Standard 17.5%,
Custom.
If custom is selected the user must be able to select the tax rate from a
list between 1% and 20%
Cell i10 must be 0 if E10 is none, must be G10 divided by 1.175 if E10 is
standard and finally G10 divided by 1.user defined value if custom is
selected ( eg if user selected 5%would be G10/1.05 ).

Please somebody help me