More math than formula but I could really use your help please

[Carlos5]

Hello, I started to write a formula but realized that I don't even know where to start with the math. Please help.
Here is the problem. I offer 10% off of the price for all people during a sale. Members get 15% off. the problem is that the 10% is automatically figured so to get to 15% from the original price I would have to take x% off from the discounted price. How do I figure x? (Example in numbers: item is $10.00, 10% off = $9.00, what % off from the $9.00 do I use to get to 15% off of $10.00? (i.e. to $8.50)
I hope that makes sense.
Thanks,
Carlos
(edit: spelling)

 

[Candyman8019]

I would probably figure out 1% of the original price...then you use either 10x that or 15x that value as the discount depending on if they're a member or non-member.

 

[Legacy 143009]

The formula will be:
Lower discount applied price - (original price×(higher discount rate - lower discount rate))
For example let say original price is 100. You applied 10% and dropped to 90.
90-(100*(0.05))=85
I hope this makes sense. Take care

 

[Legacy 143009]

In addition if you want to find x% rate directly, the formula will be:
90-90*x = 85
90x = 5
x = 1/18

 

[kevin9999]

Book1
	A	B	C
1	Original price	Discounted Price	Members Price
2	$10.00	$9.00	$8.50
Sheet1

Cell Formulas
Range	Formula
B2	B2	=A2*0.9
C2	C2	=B2/9*8.5

 

[Carlos5]

Thank you everyone!