mathprobability
posted by ASh .
Mary has 3 boxes with Marbles. Eavh box is labeled so that she knows what is in each box. She has 1 box with 2 blue marbles, another box with 2 red marbles and a 3rd box with 1 red and 1 blue marble. Mary's little sister removed all the labels and she placed them back incorrectly.
IS it possible for Mary to reach for only 1 marble, look at it and determine which box is which?

I don't think so. No matter which one marble she pulled out, she still wouldn't know which of two boxes it was in.
I Googled this problem  but didn't find any sites that met the criteria you've set up.