Hopefully someone on this forum can help me. I've already posted this same question on other forums, but nobody has even replied. I hope I don't stump y'all also.
( I even have a picture for you to look at to see what I'm referring to... )


I have a column of values (E4:E87). I'm adding 1 value to this column manually each day...so tomorrow (July 24th) I will have E4:E88...and so forth. Each day is a new row.

In column Z (i.e. cell Z87) I have the formula =(SUM(O53:O87))/(SUM(E53:E87)). Z88 will have
=(SUM(somevalue:O88))/(SUM(somevalue:E88)). This gives me a resulting percentage for a rolling period of time.

I need an automated way to populate "O53" and "E53" ("somevalue") in the formula so that the SUM of the current row's cell (i.e. E88) through [whatever] is 50 or greater. (The sum of the values should be as small as possible, but at least 50, and should not include any older values than absolutely necessary for it to equal at least 50.)

An image of my spreadsheet can be viewed here:

http://goo.gl/1tw4mI



Thanks for your help!

-rbtfinley