Retrieve most recent of multiple rows

[Norah Jones]

I have a table which looks like this:

    answer_id  q_id  answer  qscore_id  answer_timestamp
    1          10    Male    3          1363091016
    2          10    Male    3          1363091017
    3          11    Male    3          1363091018
    4          10    Male    3          1363091019
    5          11    Male    3          1363091020
    6          12    Male    3          1363091020
    7          11    Male    3          1363091025

So I have multiple answers for the same questions (q_id). I want to be able to retrieve
only ONE answer per question and that be the most recent answer.
There should be THREE rows returned, which are all the most recent answered for that q_id:

    4          10    Male    3          1363091019
    6          12    Male    3          1363091020
    7          11    Male    3          1363091020