Excel 2007 Visual Basic: minimum values

Question

Here's sample sheet:

ColA, ColB, ColC
A, 0.2, 10%
A, 0.3, 1%
A, 0.5, 6%
B, 0.4, 9%
B, 0.3, 8%
B, 1.2, 40%

I have to find minimum value in ColB for specified value in ColA , then check if ColC in this row is greater than 15%. If so - return value of ColB . If not, find next minimum value and sum with previously found value, then again check if sum is greater than 15%, and so on.. Return last summed value from ColB .

Example (for ColA =" A "):
1. find minimum value in ColB (cell: B2, value 0.2)
2. check if value in ColC in this row (cell: C2, value 10%) is greater than 15% (not met!) sum with previously val = 0 + 10% = 10%
3. take next minimum value in ColB (cell: B3, value 0.3)
4. check >15% condition -> (cell: C3, value 1%) sum with previously val = 10% + 1% = 11% (still not met)
5. take next minimum value in ColB (cell: B4, value 0.5)
6. check >15% condition -> (cell: C4, value 6%) sum with previously val = 11% + 6% = 17% (condition met)
7. The last cell we summed was C4, so we return value from ColB in this row - 0.5

(Answer for "B" is 0.4)

I'd like to ask for any hints to solve this problem. Hope it's clear ;)

Here's the prototype of my function
Function foo(ColA As String) As Integer

Answer 1

Function Foo(rng As Range, ColA As String, Target As Variant) As Variant
    Dim Dat() As Variant
    Dim r As Long, c As Long
    Dim sm As Variant

    ' Get Data from sheet
    Dat = rng.Value2
    ' Sort DAT on column B
    ' <sort code here>

    sm = 0#

    ' Loop through rows
    For r = LBound(Dat, 1) To UBound(Dat, 1)
        ' If Column 1 matches
        If Dat(r, 1) = ColA Then
            ' sum of column 3
            sm = sm + Dat(r, 3)

            ' If target reached
            If sm >= Target Then
                ' Return result
                Foo = Dat(r, 2)
                Exit Function
            End If
        End If
    Next

    ' Target not reached
    Foo = "No Answer"

End Function

Call function like this (replace $A$1:$C$6 to suit your sheet)

=Foo($A$1:$C$6,"A",15%)