### Crack the lock code

• Does any one know how to crack this? I got this as a challenge.

Welcome to Puzzling!

Reminds me of the game of Mastermind

**Hard mode**: as delightfully noted by @JollyJoker in his/her answer below, this problem is overdetermined and can be solved by omitting clues 4 and 5, the insight for which makes it a far more beautiful puzzle. Try it that way first.

this is pretty easy variation of mastermind question, i am not sure what the difference is? this is also called Electronic Mastermind (Invicta).

4 years ago

The code is:

042

Explanations:

One number is correct and is also correctly placed:

2

One number is correct but wrongly placed:

4

Two numbers are correct and wrongly placed:

0 & 2 incorrectly placed

Nothing is correct:

None of them are in the code

One number is correct but wrongly placed:

0

Approach/Thought Process Chosen

682 - One number is correct and well placed

Correct Number's array - 6,8,2
Confirm Number's array -

614 - One number is correct but wrong placed

Correct Number's array - 8,2,1,4(6 is removed since this clue contradicts the previous one and hence 6 should not be present even in the code-The position of 6 is same in Clue 1 and 2 which mean's it can be pushed out of scope)
Confirm Number's array -

206 - Two Numbers are correct but wrong placed

Correct Number's array - 8,2,1,4,0
Confirm Number's array - 0_2(Since 6 is out of scope, consider 2 and 0 to be in the confirm array list and clue 1 says 2 is well placed )

738 - Nothing is correct

Correct Number's array - 0,2,1,4(8 is removed from the array)
Confirm Number's array - 0_2

780 - One Number is correct but wrong placed

Correct Number's array - 0,2,4(Clues 3 and 5 confirms the position of 0 to be the first. Clues 1 confirms the position of 2. Clue 2 confirms the position of 4 and hence 1 is removed from the list)
Confirm Number's array - 042

It may just be me... but in my opinion your explanation does not actually explain anything. "One number is correct and is also correctly placed", but _why_ is this specific number the one that's correct, why not any of the other two?

@StephanBijzitter-It's just that I posted the answer first with the explanation part later(check the edits). But there were better answers(like this),so didn't feel that I need to add anything else. This one is accepted only due to the reason that it was first. Also, the puzzle was a simple one so I thought I can just post the answer with the reasons.

@StephanBijzitter- I have solved many of these recently. I never thought it would require any explanation. But, thought later to add some. Here's one I solved recently last month sample Also, accepting the answer is not my call for sure. You can check out one of my comment where I appreciated the other answer.

@StephanBijzitter- Hope the update doesn't disappoint you. Thanks for pushing me to do that :)

How you confirmed it in 1 and 4

@StephanBijzitter Valid point.

The explanation makes this answer so much better :-)