Enigma 1517: Just forgotten
17 September 2012
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From New Scientist #2679, 25th October 2008
Joe was furious when he forgot one of his bank account numbers. He remembered that it had all the digits 0 to 9 in some order, so he tried the following four sets without success:
When Joe finally remembered his account number, he realised that in each set just four of the digits were in their correct position and that, if one knew that, it was possible to work out his account number.
What was it?