Formula to get average based on IF criteria

[Obewan]

I need a formula which works as follows:
=if anything in column X=1 and column AC=1 (i.e. both must = 1) then I want the average of the corresponding number in column Y

Tried these but to no avail - just used 200,000 as the length because it's close to 200,000 rows of data
=IF(AND(X9:X200000,1,AC9:AC200000,1),AVERAGE(Y9:Y200000))
=AVERAGEIF(AND(X9:X200000,1,AC9:AC200000,1),Y9:Y200000)

thanks in advance

Seamus

 

[Peter_SSs]

Try

=AVERAGEIFS(Y9:Y200000,X9:X200000,1,AC9:AC200000,1)

 

[Obewan]

Prefect!! Thanks

 

[Peter_SSs]

Cheers.