Days to percentage goal

[quhectic24]

Hello, I searched the forums for this answer but either found old threads with no answers or something different than what I am looking for.

I am trying to calculate how many consecutive days it will take to get to a specific percentage goal.
I am currently on day number 420 of a project. 46 of these days I was unable to meet my goal for the project (equates to 10.98%).
My question is, how many days consecutively would it take for me to get to where I am not meeting my goal for exactly 10% of the overall days. (Image attached)

I can manually get to the answer of 41 however I am having issues finding the correct formula in excel due to the overall amount of days increasing.

 

[lrobbo314]

How about this?

Book1
	A	B	C	D	E	F
1	Goal Met (Days)	Gol Not Met (Days)	% Not Met	Goal %		Consecutive Days to Goal
2	373	46	10.98%	10%		41
Sheet1

Cell Formulas
Range	Formula
C2	C2	=B2/(B2+A2)
F2	F2	=((B2-(B2*D2))/D2)-A2

 

[quhectic24]

How about this?

Book1
	A	B	C	D	E	F
1	Goal Met (Days)	Gol Not Met (Days)	% Not Met	Goal %		Consecutive Days to Goal
2	373	46	10.98%	10%		41
Sheet1

Cell Formulas
Range	Formula
C2	C2	=B2/(B2+A2)
F2	F2	=((B2-(B2*T

Thank you! Perfect!