This lock has a 3 digit code
Can you crack it
using only these hints? 2 9 1
One number is correct
and in the right place,
2 4 5
One number is correct
but in the wrong place,
4 6 3
Two numbers are correct
but in the wrong place, 5 7 8
Nothing is correct, 5 6 9
One number is correct
but in the wrong place.
Answers
In the Case (4) “5-7-8 nothing is correct in.”
As no number is correct in it. So, 5, 7 and 8 are removed or eliminated from all the cases.
Now,
Case (1)
“2-9-1 one number is correct and is in the right place.”
At present we don't know which one is correct. Now, let's move to another case.
Case (2)
“2-4-5 one number is correct but in the wrong place.”
From Case (1) and (2)
2 is at the same place and in one case one digit is right and at the right place while in another one digit is right but at the wrong place. So, 2 can't be the number.
Case (3)
“4-6-3 two numbers are correct but in the wrong place.”
From Case (2) (3) and (4) we can say the in Case (2) 4 is the right digit but at the wrong place. So, instead of the second position, it can be at first and third place or position. But from Case (3) it can't be in the first position too. So, it means 4 is in the third position.
Case (5)
“5-6-9 one number is correct but in the wrong place.”
From Case (4) 5 is already removed. So, the correct number or digit can be 6 or 9.
Now, from Case (3) and (5) 6 is also wrong as it at the same place. So, in Case (3) correct numbers are 4 and 3 but then wrong place.
And in Case (5) 9 is the correct number but at wrong position or place.
So, we have correct numbers = 4, 3 and 9.
And in Case (1) one number is correct and is at the right place. From the above information, we can say that 9 is the correct number and is at the right or correct position too.
Therefore, the correct code is 394.