
Percentage problem
Hey guys, this my first post here and I hope that there is someone that can help me with a problem that I came across. I'll try to explain :)
Basically I haveis one table with two rows. At one point of the table I have percentage P1 of sums of all previous values of x and y rows. At some other point I have second percentage P2, but also I know the values of x and y which made percentage increase... The problem here is to find what is the value of 1% at second point.
If we say that Sx is sum of x row, and Sy sum of y row, that percentage at some point is P=Sx/(Sx+Sy)... Just so you know what percentage am I talking about :)
Here is a picture of a table: http://img221.imageshack.us/img221/3903/percent.jpg
I hope that someone could help me with this one :) I guess that I just get lost somewhere in my calculations :)
Thanks...

Hi,
It's curious that you use the word "row" to mean "column" and "point" to mean "row"...
Please tell us if the following rephrasing is correct. You have two sequences of numbers: $\displaystyle x_1,\dots,x_n$ and $\displaystyle y_1,\dots,y_n$. Also, there is a number $\displaystyle k < n$. Let $\displaystyle X_k=x_1+\dots+x_k$, $\displaystyle Y_k=y_1+\dots+y_k$, $\displaystyle X_n=x_1+\dots+x_n$, $\displaystyle Y_n=y_1+\dots+y_n$. Also, let $\displaystyle P_1=X_k/(X_k+Y_k)$ and $\displaystyle P_2=X_n/(X_n+Y_n)$. Do you need to find $\displaystyle X_n+Y_n$, or $\displaystyle 0.01(X_n+Y_n)$ in the end?
If so, let $\displaystyle X=X_nX_k$ and $\displaystyle Y=Y_nY_k$. Then you have two equations:
$\displaystyle X_k/(X_k+Y_k)=P_1$
$\displaystyle (X_k+X)/(X_k+X+Y_k+Y)=P_2$
with two unknowns $\displaystyle X_k$ and $\displaystyle Y_k$, so the equations can be solved.

Hi emakarov, thanks for your answer :) I'm sorry for swapping row and column, about the point, I meant as a point in the time, since values are added every few seconds, as table changes all the time... Just that wasn't the issue so I didn't mentioned it :)
About the solution, funny thing is that I solved it 15mins ago... I guess that sometimes is a good thing to take a break :) You are right about the problem, and you described it very good... My solution went in a bit different way, but end result is the same, so thank you very much...
Oh, and sorry if my English is not perfect, it's not my native language :)
Thank you very much again...