I have 2 columns in a spreadsheet. Column 1 has values of (A, B or C),
Column 2 has numeric values. In one cell I want to calculate the maximum
value for all of rows where column 1 = "A".

Example:

column 1 column2
A 10 A Max = 15
A 5 B Max = 9.25
B 3 C Max = 3
C 2.5
B 9.25
C 3
A 15

How can I calculate this?