Ok, I should have simplified the table. here it is

Date Running Total %
7/27/2010 612 10.7
7/28/2010 663 11.6
7/30/2010 867 15.2
8/25/2010 1,377 24.1
8/26/2010 1,734 30.4
8/27/2010 2,346 41.1
8/28/2010 3,009 52.7
9/30/2010 3,519 61.6
10/1/2010 3,876 67.9
10/2/2010 4,488 78.6
10/3/2010 5,712 100.0
..
Input Boxes & expected answers for the following questions :
1 From the cumulated % Column. By what date will I reach 30% or
less ? Answer : 8/25/2010
..
2. From the Running Total Column. By what date will I reach 3,000 or
Less ? Answer : 8/27/2010
..
3. From the Date Column. What will be the running total & % by
9/01/2010 or earlier ? Answer : 3,009 and 52.7
..
Thank you for your help