"We like their horses."
Translation:Vi tycker om deras hästar.
Their is suggested as deras, sitt, sin, used sin, duolingo says its wrong, why?
sin, sitt and sina refer back to the subject, and in this case the sentence does not say that they like their own horses, but we like their horses, so it can't be used here. Think of it as his/her/their own.
"Vi tycker deras häster om" is wrong. But, please explain me why. Is this version for questions only?
Tycker alone means "think," and om means "of" or "around," so in the statement form, you're essentially saying that "We think our horses of," rather than the literal statement "We think of (or like) our horses." So yes, that form would only be used in questions