Its simple
You know that all jar has mislabelled, so there is no mixed fruit in mixed jar, take one fruit from mixed labelled jar, there is only two possibility fruit should be apple or orange , but you know that apple is not in apple labelled jar and orange is not in orange labelled jar, if fruit is apple in mixed labelled jar, then orange is in apple labelled jar and mixed fruit is in orange labelled jar, and if fruit is orange then apple in orange labelled jar and mixed fruit in apple labelled jar,
So you can rearrange by just one try