A Macro to Copy and paste from cell above if certain Conditions are met

Hi

I am new to VBA and not sure if I can achieve what I am looking to do in a macro.

I am looking for a macro to copy and paste text from the nearest cell to the first cell below that meets two conditions.

I have shown a very simple example of what I would like the macro to look like before and after macro run.

It may seem simple but its a question of quantity hence the need for macro - I have over 30,000 rows in the spreadsheet.

e.g.

Cols A & C are the conditions to be met 25 & a
Col B is the text to be copied if condition met.

Before Macro

.............Col A.........B...........C
Row
1................25.....Folder A.....a
6................25.....................a
10...............25

After Macro

.............Col A.........B...........C
Row
1................25.....Folder A.....a
6................25.....Folder A.....a
10...............25


Thanks in advance.

Denise