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Puzzle 35 - Solution

 The puzzle was

Here is a numeric lock. And here are the results of various number combinations.

  1. 682 - one digit is right and in the right position.
  2. 614 - one digit is right but in the wrong position.
  3. 206 - two digits are right but both are in the wrong positions.
  4. 738 - all digits are wrong.
  5. 380 - one digit is right but in the wrong place
So what is the correct code to open the lock?
 
The correct number is 042.

Now let us see how we get this solution
  • 682 and 614 have common as 6. But first hint says the digit is in right place and second says, it is in the wrong place. So 6 is not the correct digit
  • 206 says two digits are correct but in wrong place. Which means 2 and 0 are correct digits (6 is not correct)
  • 738 says all digits are wrong and 380 says one digit is right but in the wrong place. 7 and 3 and 8 are all wrong. So only 0 is the correct digit. And 0 is not in the third place.
  • 0 is not in the place, it is not in second place (rule 3). So it should be in first place. 
  • 2 is the correct digit and it is in last place.  (rule 1). 
  • One digit in rule 2 must be the correct digit. It is not 6. It is not 1 as 1 is already in the middle position. So digit must be 4. 
  • Our solution is 042

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