Weighted SUM of filtered table

[zsnemeth]

Dear All,

how do I calculate a SUM of 2 columns (for Ex A&B) if there are in the col A % values (as weighting) and in the col B the real values, which have to be multiplied (weighted) by the col A.

If the table is filtered (as the formula SUBTOTAL can handle), how do I get my SUM of the whole table of col B weighted?
How do I do this, if my data is formed as a table?

Thanks in advance!

Cheers,
Zsolt