Quantitative Aptitude :: Probability - Discussion

There are three boxes containing red, white and mixed balls, which are mislabelled. It is known that one of the boxes contains only white and one only red balls. The third contains a mixture of red and white balls. You are requested to correctly label the boxes with the labels Red, White and Red & White, by picking a sample of one ball from only one box. What is the label on the box you should sample ?