In front of you are 3 boxes. One box contains only apples, another box contains only oranges, and the last contains both apples and oranges. The first box has the label "apples," the second "oranges," and the third "apples and oranges." Unfortunately, all of the labels are wrong. Your job is to fix the labels. You are not allowed to peek inside any of the boxes. But you can ask for a sample from any box. You point to a box, and you get a fruit from that box. What is the minimum number of samples you need to label all of the boxes correctly? Thanks for help.
+9466 This is an interesting question!!
They told us all of the labels are wrong.
That means that the box labeled " apples and oranges " does not have both apples and oranges. Instead, it must be all apples or all oranges.
So ask for a sample from the box labeled " apples and oranges ." If you get an orange, then the box must be all oranges. (If you get an apple, the box is all apples.)
So...let's swap the label on the box that was originally labeled " apples and oranges " with its correct label that you know now.
That leaves one label untouched. We know that it is incorrect, since all the labels were wrong to begin with. So, swap this label with the " apples and oranges " label.
Now they are all correct! And we only needed one sample. 
Only one sample is sufficient!. Take a sample from the box labeled "apples and oranges". Whatever the sample is, that is right label for that box, since they are all labeled wrong. For example, if the sample was an apple, then that box contains only apples. The other two boxes are labeled "apples" and " oranges". Now we go to the box labeled "oranges". Since we have labeled the first box correctly as "apples", then that box must be "apples and oranges". And the remaining box labeled "apples" must be "oranges".
+9466 This is an interesting question!!
They told us all of the labels are wrong.
That means that the box labeled " apples and oranges " does not have both apples and oranges. Instead, it must be all apples or all oranges.
So ask for a sample from the box labeled " apples and oranges ." If you get an orange, then the box must be all oranges. (If you get an apple, the box is all apples.)
So...let's swap the label on the box that was originally labeled " apples and oranges " with its correct label that you know now.
That leaves one label untouched. We know that it is incorrect, since all the labels were wrong to begin with. So, swap this label with the " apples and oranges " label.
Now they are all correct! And we only needed one sample.
Sorry, hectictar! I didn't know you were answering it at the same I was! Otherwise, I wouldn't have touched it.
+9466 There's no need to be sorry Guest!! It can be helpful to have more than one answer, in case the questioner doesn't understand one of them!
You seem really nice ...Is there a reason why you haven't gotten an account on here? But...I can understand just wanting to be anonymous too.
