Answer: 22m + 20
First average the 2 package weights:
(12m+12) + (14m + 12) / 2
(26m + 24) / 2
13m + 12
So the average weight of 2 package is 13m + 12
Now you already know the average of 6 packages that is 9m + 8. So add the 2 package and 6 package average weights.
13m + 12 + 9m + 8
22m + 20
I am not sure unless you or someone else thinks it correct. But thats it, pls forgive me if i am wrong... :(