Free Coding and Decoding MCQs with Answers

11. Using the same code, in which 'som' means bring and 'jo' means cold, what does 'ho' mean in 'som ho jo'?

• A. water
• B. drinks
• C. is
• D. me

Explanation: The phrase means bring cold drinks, and with som as bring and jo as cold, the only word left is ho, which must be drinks. Elimination is the natural final step once the other words are pinned down. Each new sentence in such puzzles removes one more unknown.

12. If EARTH is coded by replacing each letter with the one three places ahead, the code is

• A. HDUWK
• B. BXOQE
• C. HDUWJ
• D. FBSUI

Explanation: E becomes H, A becomes D, R becomes U, T becomes W and H becomes K, each three places forward. This particular shift is the Caesar cipher, historically used by Julius Caesar. Working letter by letter and writing the alphabet out in full prevents miscounts.

13. In a code, DELHI is written as CDKGH. Which rule has been applied?

• A. one place forward
• B. one place backward
• C. two places backward
• D. reversal of the word

Explanation: D becomes C, E becomes D, L becomes K, H becomes G and I becomes H, each one place backward. Checking the last letter as well as the first guards against a rule that only appears to fit. A reversal would produce IHLED instead.

14. If the code for LAMP is MZNO, the rule is that

• A. every letter moves forward one place
• B. consonants move forward and vowels move backward one place
• C. every letter moves backward one place
• D. the word is reversed

Explanation: L becomes M and M becomes N, both forward, but A becomes Z and P becomes O, which is backward, so the rule depends on whether the letter is a vowel. Mixed rules of this kind are common at the harder end of coding questions. Testing each letter separately rather than assuming one uniform shift is essential.

15. If 24 is coded as 66 and 35 is coded as 88, then 47 is coded as

• A. 1111
• B. 112
• C. 1112
• D. 121

Explanation: Each digit is added to give a sum, which is then written twice, so 2 plus 4 is 6 giving 66, and 3 plus 5 is 8 giving 88. For 47 the sum is 11, which written twice gives 1111. Confirming a numeric rule on both examples before applying it is what avoids guesswork.

16. In a certain code, 5 is written as 25 and 6 is written as 36. What is 9 written as?

• A. 18
• B. 81
• C. 90
• D. 99

Explanation: Each number is squared, since 5 squared is 25 and 6 squared is 36, so 9 becomes 81. Doubling would give 18, which is the trap in the first option. Always test a rule against every example given rather than only the first.

17. If PEN is coded as 35 by adding the alphabet positions of its letters, what is the code for CAT?

• A. 24
• B. 26
• C. 27
• D. 23

Explanation: C is 3, A is 1 and T is 20, so the sum is 24. Checking the example, P is 16, E is 5 and N is 14, which sums to 35 and confirms the rule. These questions reward knowing the alphabet positions without having to count from A each time.

18. If in a code MOTHER is written as PRWKHU, the shift applied is

• A. two places forward
• B. three places forward
• C. three places backward
• D. one place forward

Explanation: M becomes P, O becomes R, T becomes W, H becomes K, E becomes H and R becomes U, every letter advancing by three. Checking all six letters rather than just the first is what confirms the rule. A backward shift of three would have given JLQEBO instead.

19. If BAT is coded as YZG, the rule is that each letter is replaced by

• A. the letter three places ahead
• B. the letter three places behind
• C. its opposite letter in the alphabet, A for Z and B for Y
• D. the next vowel

Explanation: B pairs with Y, A with Z and T with G, each letter being replaced by its mirror image counting from the other end of the alphabet. The check is that the positions of the pair always add to 27. This atbash style code appears regularly and is easy to recognise once the sum rule is known.

20. In a code, WATER is written as XBUFS. Following the same rule, FIRE is written as

• A. GJSF
• B. EHQD
• C. GJSG
• D. GKSF

Explanation: Each letter advances by one, so F becomes G, I becomes J, R becomes S and E becomes F. The example confirms the rule on all five of its letters. Consistency across the whole example is what distinguishes a genuine rule from a coincidence.