Trying to calculate tax and grat involved in set selling price.

I would like to be able to key in a total price which includes a 5% tax and a 15% gratuity, and shows the actual amounts for the tax, grat and the selling price

For instance

If the total sale including selling price, 5%tax and 15%grat = $1
5%tax would be $.05
15%Grat would be $.15
and actual sell price would be $.80

I tried to make a spreadsheet that I can type in an all-inclusive price and the calculations would break down the actual sell price amount, tax amount and grat. amount, but the numbers are not working properly for the 5%tax and 15%grat.

Could someone please have a look and tell me where I have gone wrong please?

Appreciate it!

Jim

What if the tip is based on the pre tax amount?

Never mind, I realized the mistake I was making.
B9: =B5/(1+(B3+B4))
BTW, this forum is great far a noob like me. I appreciate everyone's posts!