Can you crack the 3 digit number lock puzzle with 548 in five hint clues? Each has a 3 digit hint code and digit position and correctness description.
The 3 Digit Number Lock Puzzle with 548 in Clues
From the five clues, find the 3 digit code that will open the number lock.
Clue 1: Code 548: One digit is right and is in its place.
Clue 2: Code 806: One digit is right and is in the wrong place.
Clue 3: Code 530: All digits are wrong.
Clue 4: Code 157: Two digits are right, but both are in the wrong place.
Clue 5: Code 647: One digit right and is in the wrong place.
Crack the code to open the number lock. Try for the minimum step solution.
Time: 20 minutes for the minimum step solution.
Hint: Useful pattern identification and leveraging the pattern into effective methods lie at the heart of inventive problem solving of any scale.
Result: Two of the leading AIs in the world failed to pass this simple test of arriving at the inventive problem solving by a long mile, today on 16th August, 2025 at about 0130 hrs IST.
Minimum Step Solution to the 3 Digit Number Lock Puzzle with 548 in Clues
Reason says, the first step in solving the puzzle must be to find a correct or incorrect digit, as,
- Trying to know the correct position without knowing the correctness of the digit is senseless.
- Finding an incorrect digit might well lead to finding correct digits from a new clue.
As a next step of strategic problem solving, it stands to reason to:
- Identify maximum number of correct digits at one go.
Step 1. Identify two correct digits at one go
Clues 3 and 4 give you two correct digits.
Clue 3: Code 530: All digits are wrong.
Clue 4: Code 157: Two digits are right, but both are in the wrong place.
- With digit 5 wrong in Clue 3, the digits 1 and 7 must be correct in Clue 4.
- Digit 1 can occupy either the middle or the rightmost positions; digit 7 can occupy either the leftmost or the middle positions.
Step 2. Identify the third correct digit and its position - crack the code
From Clues 1 and 5, Digit 4 is wrong:
Clue 1: Code 548: One digit is right and is in its place.
Clue 5: Code 647: One digit right and is in the wrong place.
- Digit 4 cannot be right and occupy the same position in both clues with conflicting position descriptions. This is identification of an incorrect digit by the well known pattern of position and correctness conflict of a digit in two clues appearing in same position.
- As in Clue 1, digits 4 and 5 both are wrong, digit 8 must be the single correct digit in its right position in the lock opening code.
- Continue your reasoning based on valid probable positions of the two correct digits 1 and 7 (as in the second conclusion in the first step). As the rightmost position is grabbed by digit 8, digit 1 has now the only valid middle position, and digit 7 the leftmost.
- The lock opening code is 7 1 8.
The puzzle solved in just two steps without using Clue 2.
Follow the inventive principle of free resource use to verify your lock opening code against the unused Clue 2.
Clue 2: Code 806: One digit is right and is in the wrong place.
- Digit 8 is the single right digit and indeed is in the wrong place. Code 718 verified.
Learnings
- Identifying maximum number of correct digits using multiple clues: Identifying digits 1 and 7 as two correct digits in the first step using the two clues 3 and 4 followed commonsense and is nothing special.
- The key incorrect digit identification: The commonly used pattern of position and correctness conflict of a single digit appearing in two clues in the same position identified the key incorrect digit 4. Use of this pattern in solving number lock puzzles is also common.
- Extracting maximum information when analyzing a given situation: Continuing analyzing the two clues 3 and 4 to draw the second conclusion on position restrictions of the two correct digits 1 and 7 in the first step eventually made the real difference between an unusual and an usual solution. The minimum step solution in this case could be reached in two steps, though the second step had a cascade of conclusions.
The key to quick solutions of reasoning puzzles is processing the most suitable clue or condition either individually or together with other clues.
To enjoy solving many more such number lock puzzles, click here.
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