Quote Originally Posted by Rick Rothstein View Post
Give this formula a try...

=SUMPRODUCT((A$2:A$10&B$2:B$10=A2&B2)*C$2:C$10)/SUMPRODUCT(1*(A$2:A$10&B$2:B$10=A2&B2))
Actually, in thinking about it a little more, to avoid the possibility of a false match between those concatenations, use this modification of the formula instead...

=SUMPRODUCT((A$2:A$10&CHAR(1)&B$2:B$10=A2&CHAR(1)& B2)*C$2:C$10)/SUMPRODUCT(1*(A$2:A$10&CHAR(1)&B$2:B$10=A2&CHAR(1) &B2))