Possessive Case: The blue car is Marcus'

Hello, I have a question about the Possessive Case. Are the following sentences correct?

The blue car is Marcus'.
That yellow purse is Martha's.

Nesta aula, o professor Denilso de Lima, autor do livro "Combinando Palavras em Inglês", ensina como as collocations (combinações de palavras) podem ajudar você a falar inglês com mais naturalidade. ACESSAR AULA
1 resposta
Yes they are correct.
If you are finding them strange it's because you aren't used to them. These type of structure may sound more natural as short answers, but yours are totally fine.
. Whose phone is that?
. It's John's. (abbreviation of "That phone is John's").