How do I add cell values using conditional criteria?

[Guest]

Here's my sheet

Company|Zone | Units
________________
A | 1 | 3
B | 2 | 4
A | 3 | 2
A | 1 | 7

What I want to do is get the average number of units from Company A in Zone 1.

Can somebody help me?

 

[Bob Phillips]

=SUMPRODUCT(--(A2:A20="A"),--(B2:B20=1),C2:C20)

--
HTH

Bob Phillips

(replace somewhere in email address with gmail if mailing direct)

 

[Guest]

=AVERAGE(IF((A1:A100="A")*(B1:B100=1),C1:C100))

ctrl>shift>enter (not just enter)