Can you take up the challenge and crack the 3 digit number lock code to open the number lock with least number of clues? Good logic analysis is the key.

## Challenge to Crack the Number Lock Code Using Least Number of Clues: The Puzzle

Find the 3 digit code from the five clues to unlock the number lock:

**Clue 1: Code 4 6 0 :** One digit right and in right position.

**Clue 2: Code 4 9 2 :** One digit correct but in wrong place.

**Clue 3: Code 0 8 4 :** Two digits right but wrongly placed.

**Clue 4: Code 5 1 6 :** Nothing is correct.

**Clue 5: Code 5 6 8 :** One digit correct but in wrong place.

### Solution to 3 digit number lock puzzle 460 with 5 clues: Use least number of clues

#### Step 1: Identify the first incorrect digit

From Clue 1 and 5, digit 6 is wrong due to correctness and positional conflict. So, one of 0 and 4 is correct.

**Clue 1: Code 4 6 0 :** One digit right and in right position.

**Clue 5: Code 5 6 8 :** One digit correct but in wrong place.

**Digit 6 is wrong**due to**positional conflict between two clues**.*It cannot be right and occupy same position in both clue codes.**Either of digits 0 or 4 is correct.*

#### Step 2: Identify the first correct digit

From Clue 3, digit 8 is right.

**Clue 3: Code 0 8 4 :** Two digits right but wrongly placed.

- As one of 0 and 4 is correct, the other correct digit must be 8.

#### Step 3: Identify the position of the correct digit

From Clue 3 and 5, digit 8 takes the first place.

**Clue 3: Code 0 8 4 :** Two digits right but wrongly placed.

**Clue 5: Code 5 6 8 :** One digit correct but in wrong place.

- In the two clues together,
**positions second and third are wrong for digit 8**, so*its position in the correct code must be the first.*

#### Step 4: Identify the second incorrect and the second correct digits

From Clue 1 and 2, digit 0 is correct.

**Clue 1: Code 4 6 0 :** One digit right and in right position.

**Clue 2: Code 4 9 2 :** One digit correct but in wrong place.

- D
**igit 4 is wrong due to correctness and positional conflict in the two clues.***It cannot occupy the same position in both clues and be a correct one because of opposite position description.* - From Clue 1,
*digit 0 must be the second correct digit occupying third position.* **Code of form 8 ? 0.**

#### Step 5: Identify the third correct digit and crack the code

From Clue 2, digit 2 is the third correct digit.

**Clue 2: Code 4 9 2 :** One digit correct but in wrong place.

**One of 2 or 9 must be correct and the correct digit is in wrong position.***For digit 9 no place is available in the correct code because positions 1 and 3 are already taken up.***Digit 2 must be the third correct digit taking up second position.**

**Code** to open the number lock is **8 2 0.**

*Verify the code against the 5 clues.*

**Note:** **Only 4 clues are used.** Clue 4 remains unused. This is the hallmark of **efficient solution using least number of clues** *by watertight logical reasoning.*

### Puzzles you may enjoy

#### Easy to hard brain teasers with systematic solutions

**Challenging brain teasers with solutions: Long list.**

This will always be the **most up-to-date full list** with the brain teasers **classified into categories** that can be browsed separately.