Tumblr answers (or "notes" as they're more frequently called) are Tumblr's flavour of blog comments. A user who wants to leave a message on another user's Tumblr blog post can either leave a note or reblog the item on her own blog with a note. If you want to delete a note someone left on your own Tumblr blog post, you can do so in just a few steps.
Sign into your Tumblr account at tumblr.com.
Click on the "# posts" link on the right side of the screen. The "#" will be a number representing the number of posts you have on your Tumblr blog.
Scroll through your posts and locate the post that has a note you'd like to delete, then click the "Notes" link at the top of the post's box.
Hover over the note and click the "Block" link. The note will be removed from the post.