Free Coding and Decoding MCQs with Answers

1. If CAT is coded as DBU, then DOG is coded as:

• A. EPH
• B. EPG
• C. DPH
• D. FQI

Explanation: Each letter moves forward one position in the alphabet: C→D, A→B, T→U. Applying the same rule to DOG gives D→E, O→P, G→H, which is EPH.

2. In a certain code, MEDICAL is written as NFEJDBM. How is HEART written in that code?

• A. IFBSU
• B. IFBTU
• C. GDZQS
• D. IEBSU

Explanation: Each letter is replaced by the one immediately after it in the alphabet, so M becomes N, E becomes F and so on. Applying the same shift to HEART gives I, F, B, S and U, which is IFBSU. Option IFBTU shifts the R correctly but moves the T two places instead of one.

3. In a certain code, CAT is written as DBU. How is DOG written in that code?

• A. EPH
• B. CNF
• C. EPG
• D. DPH

Explanation: Each letter moves one place forward in the alphabet, so C becomes D, A becomes B and T becomes U. Applying the same shift to DOG gives E, P and H. Checking the rule on all three letters of the example before applying it is what makes these questions quick.

4. If ROSE is coded as QNRD, how is LILY coded?

• A. KHKX
• B. MJMZ
• C. KHLX
• D. KIKX

Explanation: Every letter moves one place backward, since R becomes Q, O becomes N, S becomes R and E becomes D. Applying the same backward shift to LILY gives K, H, K and X. Backward shifts are the mirror image of forward ones and are equally common in tests.

5. In a code, if A is 1, B is 2 and so on, what is the sum of the letters in the word CAB?

• A. 6
• B. 5
• C. 7
• D. 4

Explanation: C is 3, A is 1 and B is 2, and adding them gives 6. Positional coding of this kind is the basis for many number letter questions, so knowing the alphabet positions fluently is worth the effort. A useful anchor is that M is 13, exactly halfway.

6. If in a code TEACHER is written as VGCEJGT, then what is the shift applied?

• A. each letter moves two places forward
• B. each letter moves two places backward
• C. each letter moves one place forward
• D. the letters are reversed

Explanation: T becomes V, E becomes G and A becomes C, each a gap of two places forward, and the same holds for the rest of the word. Testing the rule on the first two or three letters and then confirming it on the last is the efficient approach. A reversal would change the order of the letters rather than their identity.

7. In a certain code, PAPER is written as REPAP. What is the rule?

• A. each letter is shifted forward
• B. the word is written in reverse order
• C. vowels are replaced by consonants
• D. alternate letters are swapped

Explanation: Reading PAPER backwards gives REPAP exactly, with no letter changed. Reversal codes are recognised by the fact that the same set of letters appears in the output. Comparing the letter sets of input and output is the first check worth making.

8. If BOOK is coded as 2-15-15-11, how is CAP coded?

• A. 3-1-16
• B. 3-2-16
• C. 2-1-16
• D. 3-1-15

Explanation: Each letter is replaced by its position in the alphabet, so C is 3, A is 1 and P is 16. Verifying with the example, B is 2, O is 15 and K is 11, which matches. Miscounting P as 15 is the usual slip, since O is 15 and P follows it.

9. In a code language, if SUN is written as TVO, then MOON is written as

• A. NPPO
• B. LNNM
• C. NPPN
• D. NOOP

Explanation: Each letter advances by one, so M becomes N, both Os become Ps and N becomes O. The doubled letter in MOON must be coded twice in the same way, which is where mistakes creep in. Consistency across repeated letters is a useful self check.

10. If in a certain code language 'pit na som' means 'bring me water', 'na jo tak' means 'water is cold' and 'som ho jo' means 'bring cold drinks', which word means 'water'?

• A. pit
• B. na
• C. som
• D. jo

Explanation: The first two phrases share only the word water in meaning and only na in code, so na must be water. Cross referencing pairs of sentences to find the single shared element is the standard method for substitution codes. The third sentence then confirms that som is bring and jo is cold.