Which one is correct?
1. Where did you go last vacation?2. Where did you go last trip?3. Where did you go on last vacation?4. Where did you go on last trip?5. Where did you go on your last vacation?6. Where did you go on your last trip?I believe the third and fourth sentence are absolutely false, but I wanted to know if there are any other ways to ask this question.Thanks in advance.

Question

Answer

You are correct: sentnces 3&4 are wrong (should be '...on your last...'). Sentances 1&2 work, though 2 is awkward. Sentances 5&6 are the best ways to ask this question.