the apple of my friend Davi and Tom is rotten.
the apple of my friend Davi and Tom are rotten
the apples of my friend Davi and Tom are rotten
which of the setences above is right, or do you have any other suggestions?
None of them is actually correct. The best would be:
The apples of my friends Davi and Tom are rotten. (if they each have an apple or apples)
or
The apple of my friends Davi and Tom is rotten. (If they only have one apple between them)