Deleted questions are permanently deleted when we go to that page it says 'Page not found'. while in case of deleted answer it shows that answer deleted but that is still available there. they should be deleted permanently too. It may ask for confirmation to user who answered if someone else is deleting.
Questions, like answers, are not permanently deleted, but what's important to note is your access level at seeing deleted posts.
You can see your own answers on questions asked by others because you have access to that.
Users with 10,000 reputation can also see the posts of other users, questions or answers.
When you come across a question that's been deleted, unless you were the original author, have 10,000 POINTS!, or are a moderator (or SE employee), then you won't see it or its answers and it will show to you as "Page Not Found".