caculate the total for specific date

[Lowan Chan]

I would like to caculate the total in column A for those date more than 21
days until today in Column B, can anyone help?

A B
200 1/3/2010
100 2/3/2010
200 2/3/2010
50 10/3/2010
80 25/3/2010
200 1/4/2010
60 3/4/2010

thanks a lot!

 

[ozgrid.com]

Try;

=SUMIF($B$1:$B$10,"<=" & TODAY()-21,$A$1:$A$10)