Alfonso has forgotten the password of his safe. However he remembers that:

1. The number is a ten digit positive integer using each of the digits from 0 to 9 exactly once.
2. The sum of the 2nd, 5th, 6th and 8th digits is a single digit number.
3. The 4th digit is a perfect square.
4. The 3rd digit is 1
5. The sum of the 4th and 7th digits is a perfect square.
6. The value of the 10th digit is twice that of the 2nd digit.
7. The product of the 4th digit and the 6th digit is equal to that of the 2nd digit and the 10th digit.
8. 5 is next to 6 but not 4.

From the above clues, can you help Alfonso to crack the password to open the safe?

8319427056

Solved using a grid.  It would be too tedious to explain in words each of the steps, but I just went down the list and crossed out any values that were ruled out. 

Posted by tomarken on 2014-03-17 09:12:26