I have the following little table. I'd like a formula that finds the number of values where the cumulative total (of column B) is less than some threshold (tx).
I tried
{=MIN((SUM(OFFSET(B1,0,0,A1:A17))>tx)*A1:A17)-1}
but OFFSET doesn't seem to be arrayable like that. Obviously, this would be trivial with a helper column, but for certain reasons that is not possible.
So the correct answer here should be 10.
tx = .8
A B
1 0.112106465
2 0.110981698
3 0.091959216
4 0.082163441
5 0.073292066
6 0.072407529
7 0.071646289
8 0.061646797
9 0.06011448
10 0.057566381
11 0.050341978
12 0.048227061
13 0.043207335
14 0.03940462
15 0.012914194
16 0.007603446
17 0.004417003
You're not really looking for a MIN; rather it should be MAX that follows your condition.
In E7 as a standard (non-array) formula,
=AGGREGATE(14, 6, ROW(1:17)/(SUBTOTAL(9, OFFSET(B1, 0, 0, ROW(1:17), 1))<D7), 1)