I think that the problem is in fact the following. Excuse me if it is not. A person has three baskets, one with mangoes, one with apples and one which has apples and mangoes The boxes are all labeled. The vendor knows they are all labeled incorrectly. How many fruits must he take out to know which basket is which?
Answer:1. All he has to do is take a fruit from the basket that says mixed. If he gets a mango he knows that the box is mangoes (it cant be mixed because they are all wrong.) so therefore the box that says apples has mixed and the one that says mangoes has apples.