And yet, sadly, I do not recall being introduced to either otec or the word for mother. I would suggest that the standard word for the relationship should always be accepted. I suppose, though, that you could include dad, pa, da, poppa, daddy, and every other less formal term for the word father.
I put "my father's car is quicker" and was marked wrong. I was assuming that was because of faster/quicker, but reading here maybe it's because of father/dad. Either way I object! Duolingo has been accepting mother/father for mama/tata in all these questions so far so why not here, if the problem is that? And if it's faster/quicker then there's nothing wrong with quicker. Have requested that my answer be accepted.
The point is to show that táta and otec is not the same. Neither is dad and father. I am not aware of the sentences you are talking about.
Táta is introduced in Family 2. In Family 1 no sentence allows táta. If you think otherwise you would have to point to such sentence so that we could find out what is happening.