"Which car is good?"
Translation:어느 자동차가 좋습니까?
The word order is more flexible in some cases than others, but an easy way that works most of the time is to put the question word in the same place where the answer would have been.
This car is good. 이 자동차가 좋습니다.
Which car is good? 어느 자동차가 좋습니까?
In the affirmative sentence, 이 comes before the noun. Thus, 어느 comes before the noun.