help with "IF" and Checkbox Functions

[kshora]

I have 3 cells; B1 (Cost Price), C1(Margin) & D1 (Selling Price), The formula in the cell D1 to calculate the selling price is =ROUNDUP(B1/(1-C1/100),0). Let me take an example, if B1=50 (cost price) and C1=25 (Margin), my selling price derived from the formula is 67. Now if the selling prices changes to say 55, normally my Margin is same and the new selling price is 74. I need to have a choice to change the Margin to keep the selling price same, in this case to keep my selling price same as 67 the margin has to change to 17. {This can be done by using the formula =ROUNDUP(100*(1-B1/D1),0)}. For this I want to have a checkbox, if UNCHECKED the MARGIN IS SAME and the selling price increases, if the checkbox is CHECKED the MARGIN CHANGES and the selling price remains the same.

I hope the above is clear and look forward to a solution
Thanks and Regards

KShora

 

[kshora]

I also should be able to manually change cell C1 and D1

I am desperate for a solution

Regards

KShora