The are three closed boxes containing apples, bananas or both. Each box is tagged with ''apples'', ''bananas'' or ''mixed''. Altough, each box has the erroneous tag. You can open only one box to view the content.
¿What box do you open first to find the content?
The box with the tag "mixed". Open and take one fruit. Suppose it is an apple then is the apples box.