Class 10 Exam  >  Class 10 Questions  >  There is a 3-digit code to open a lock. There... Start Learning for Free
There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.
821 – One digit is correct but wrongly placed.
379 – None of the digit are correct.
486 – Two digit are correct but wrongly placed.
538 – Two digit are correct and rightly placed. 
  • a)
    528
  • b)
    845
  • c)
    485
  • d)
    548
Correct answer is option 'D'. Can you explain this answer?
Most Upvoted Answer
There is a 3-digit code to open a lock. There are four 3-digit numbers...
Without the hints, there are 1000 possible 3-digit codes (from 000 to 999). However, with the hints, we can eliminate some of these possibilities.

Let's look at the hints:

1. "One digit is correct and in its place" for the number 839.
2. "One digit is correct but in the wrong place" for the number 854.
3. "Two digits are correct but in the wrong place" for the number 369.
4. "Nothing is correct" for the number 721.

Using these hints, we can narrow down the possibilities.

For hint 1, we know that one of the digits in the code is an 8, 3, or 9. We also know that it's in the correct place. So the code must be one of the following:

- 8 _ _
- _ 3 _
- _ _ 9

For hint 2, we know that one of the digits in the code is a 5, 4, or 8. We also know that it's in the code, but in the wrong place. So the code must be one of the following:

- _ 5 _
- 4 _ _
- _ _ 8

For hint 3, we know that two of the digits in the code are a 3, 6, or 9. We also know that they're in the code, but in the wrong place. So the code must be one of the following:

- 3 6 _
- 3 _ 9
- _ 6 9

For hint 4, we know that none of the digits in the code are a 7, 2, or 1. So the code can't be any of the following:

- 7 _ _
- _ 2 _
- _ _ 1

Putting all of this information together, we can eliminate a lot of possibilities. For example, we know that the code can't contain a 2 or a 7, so we can eliminate all codes that have a 2 or 7 in them.

Using this process of elimination, we can narrow down the possibilities until we find the code that fits all of the hints.

Here's the final list of possibilities:

- 839
- 369
- 936

Of these, only one fits all of the hints: 369.

Therefore, the code to open the lock is 369.
Free Test
Community Answer
There is a 3-digit code to open a lock. There are four 3-digit numbers...

Correct code
Explore Courses for Class 10 exam

Top Courses for Class 10

Question Description
There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer? for Class 10 2025 is part of Class 10 preparation. The Question and answers have been prepared according to the Class 10 exam syllabus. Information about There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Class 10 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer?.
Solutions for There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 10. Download more important topics, notes, lectures and mock test series for Class 10 Exam by signing up for free.
Here you can find the meaning of There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer?, a detailed solution for There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer? has been provided alongside types of There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice There is a 3-digit code to open a lock. There are four 3-digit numbers and hints have been provided corresponding to those numbers to crack the code. Crack the code and mark that as your answer.821 – One digit is correct but wrongly placed.379 – None of the digit are correct.486 – Two digit are correct but wrongly placed.538 – Two digit are correct and rightly placed.a)528b)845c)485d)548Correct answer is option 'D'. Can you explain this answer? tests, examples and also practice Class 10 tests.
Explore Courses for Class 10 exam

Top Courses for Class 10

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev