Because यह is used for the doer of the action. In this sentence you (second person) would be the doer, so इस is used for सवाल, which is the thing is the thing the action is done to.
There's no 'me' in the Hindi sentence. It's literally 'give this question's answer' as stated above, so basically 'Answer this question'. You'd also need an article in front of 'answer' to make that grammatically correct: 'Give me an answer to this question' or 'Give me the answer to this question'.