>>13303244Without information, Bernard can only know certainly if his number is 5 or 6.
Albert knows Bernard doesn't know, which means his column does not include a ball in 5 or 6. Therfore delete columns A and B,and rows 5 and 6.
Now Bernard knows, which means that after the exclusions, his column has exactly one ball. Column 1 has two balls, so we exclude it from possible columns. We are now down to columns 2,3,4 and rows C, D.
Albert says he knows too. That means his row has exactly one ball, which is in C3.
