"How many will I need" Formula

[psdwit]

to try to keep it simple this is the equation I am working with
(A+B)/(A+B+C+D+E)=%

I am working this toward a goal % as the answer
EX
(A+B)(A+B+C+D+E)=15%
Goal is 10%
How many more "E" will I need to get to Goal
any help would be greatly appreciated

 

[sheetspread]

use goal seek:

Excel 2010
	A	B	C	D	E
1	7	8	19	30	36
2
3	0.15
Sheet11

Cell Formulas
Range	Formula
A3	=(A1+B1)/(A1+B1+C1+D1+E1)

Excel 2010
	A	B	C	D	E
1	7	8	19	30	84.9689
2
3	0.100692
Sheet11

Cell Formulas
Range	Formula
A3	=(A1+B1)/(A1+B1+C1+D1+E1)

 

[psdwit]

thank you however I am not sure what you mean by use goal seek. I see by the examples you went from 15% to 10% by increasing E from 36 to 85. What would be the formula to determine in order to meet goal E must increase by 49?

Thank you again

 

[sheetspread]

In the data ribbon, under what if analysis, choose goal seek, set a3 = .10 by changing e1

 

[Fluff]

Cross posted https://www.excelforum.com/excel-formulas-and-functions/1239552-how-many-will-i-need-formula.html

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