count the values in each cell of Column B but only the cells that have a value of 15

Hi, I have tried several functions but I just can't seem to find the right one I need to do this. Here is an example of what I want to do.

I have Column A and Column B, I want to count the values in each cell of Column B but only the cells that have a value of 15 in Column A. What function would I use to do this? Thanks

Hi,
Assuming the values are in say A1 to A10 and B1 to B10 then use the formula:

=SUMPRODUCT(--($A$1:$A$10=15),--($B$1:$B$10))
Regards Howard

Thanks so much for your help!