Mislabeled Boxes of Marbles

Three closed boxes have either white marbles, black marbles or both and they are labeled white, black and both. However, you’re told that each of the labels are wrong. You may reach into one of the boxes and pull out only one marble. Which box should you remove a marble from to determine the contents of all three boxes? 

 Mislabeled !

Find here how it can be done!  

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