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RRB NTPC Coding Decoding — practice questions

Explore 45 free Coding Decoding questions in RRB NTPC Reasoning. Open each question or exercise to read its content, reference answers and available explanation.

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Coding Decoding questions and exercises with answers

Showing questions 1–30 of 45.

In a Caesar cipher, what name is given to the fixed shift number?Read the answer and worked solution →In a code where each letter is replaced by the letter 3 places before it, D becomes which letter?Read the answer and worked solution →A left shift of 3 places in the alphabet is equal to a right shift of how many places?Read the answer and worked solution →Every letter is replaced by the letter 3 places earlier in the alphabet. How is FOX written in this code?Read the answer and worked solution →In a code each letter is moved 3 places back. Which word was coded as GRJMP?Read the answer and worked solution →A word is coded by moving each letter 3 places back, giving LSBO. What was the word?Read the answer and worked solution →When letters are moved 3 places back, IXWV stands for which original word?Read the answer and worked solution →In a code that moves each letter 3 places back, DOG is written as what?Read the answer and worked solution →Shifting every letter 3 places back, the word BROWN is turned into which code?Read the answer and worked solution →If every letter is replaced by the one 3 places before it, what is QUICK written as?Read the answer and worked solution →A variation of the Caesar cipher wrote A as 4 and B as 5. Which number stands for C?Read the answer and worked solution →In a code A is 4, B is 5, C is 6 and so on. How is the word BAD written?Read the answer and worked solution →In a number code with A as 4 and B as 5, the number 10 stands for which letter?Read the answer and worked solution →The ROT13 system is a Caesar cipher using a shift of how many places?Read the answer and worked solution →If each letter is moved 13 places forward in the alphabet, how is CAT coded?Read the answer and worked solution →A code moves every letter 13 places forward. What is ROT written as?Read the answer and worked solution →A message is coded with a 13 place shift and the result is coded the same way again. What do you get?Read the answer and worked solution →A text is shifted by 5 places and then by 9 places. This equals one shift of how many places?Read the answer and worked solution →Encrypting twice with shifts of 7 and then 8 is the same as encrypting once with what shift?Read the answer and worked solution →What does a brute force attack on a Caesar cipher involve?Read the answer and worked solution →Which two letters are usually the most frequent in English plaintext?Read the answer and worked solution →What does the Atbash cipher do to the alphabet?Read the answer and worked solution →If every letter is replaced by its mirror letter (A with Z, B with Y), how is CAT written?Read the answer and worked solution →In a code where A is swapped with Z, B with Y and so on, DOG is written as what?Read the answer and worked solution →Using the reverse alphabet code (A to Z, B to Y), what is SUN written as?Read the answer and worked solution →Each letter is replaced by its opposite in the alphabet (A with Z, B with Y). How is KING coded?Read the answer and worked solution →With A coded as Z and B as Y, the word LOVE is coded as what?Read the answer and worked solution →A message in a mirrored alphabet code (A with Z, B with Y) reads GSV. What does it say?Read the answer and worked solution →In a code where every letter is exchanged with its mirror letter, ZMW stands for which word?Read the answer and worked solution →Using A to Z, B to Y pairing, how is EAST written?Read the answer and worked solution →

Worked practice questions

In a Caesar cipher, what name is given to the fixed shift number?

  1. The tableau
  2. The cipher key
  3. The null symbol
  4. The homophone
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Correct answer: B. The cipher key

The size of the shift is the only secret in a Caesar cipher, so it plays the role of the key.

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In a code where each letter is replaced by the letter 3 places before it, D becomes which letter?

  1. G
  2. B
  3. A
  4. C
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Correct answer: C. A

Moving D back three places in the alphabet passes C and B and lands on A.

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A left shift of 3 places in the alphabet is equal to a right shift of how many places?

  1. 23
  2. 13
  3. 3
  4. 26
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Correct answer: A. 23

Moving back 3 places in a 26 letter alphabet ends at the same letter as moving forward 23 places.

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