"Dad, what’s this week’s winning lottery number?" asked Chloe.

"Coincidentally," her father replied, "exactly one digit in each of the five columns in the previous six winning numbers on this piece of paper is in the same position as one of the digits in this week’s winning number."

"Thanks, Dad." said Chloe, looking at the numbers over his shoulder. "But I can’t determine the number from that information."

Chloe then showed the same numbers to her mother, which were as follows:

                  
                +---------------+
                | 0  9  9  0  6 |
                | 0  1  6  9  1 |
                | 8  9  6  8  9 |
                | 0  9  6  0  9 |
                | 1  9  6  8  9 |
                | 8  6  8  8  9 | 
                +---------------+

"Your dad’s right." she said, "Exactly one digit in each of the five columns is in the same position as one of the digits in this week’s winning number, which, incidentally, is ...."

"Thanks, Mom," interrupted Chloe, "But now I know what it is."

What is this week’s winning number?

(In reply to explanation (spoiler) by Charlie)

The mother is not providing any additional information, unless Chloe somehow showed the mother a different list than the father.  The trick is that all of these digits (0,1,6,8,9) are also digits when upside down.  Chloe showed it to her mother upside down, and upside down her Mother made the same statement as the Father.  Upside down does not give rise to an unambiguous answer, but taking the two together it can be deduced.

Edited on June 27, 2013, 8:52 am

Posted by Steve Herman on 2013-06-26 15:37:57