Coding-Decoding Questions and Answers

Answer: A

The code for OBSERVE is 86.

Each letter is coded by its position in the alphabet, and a word by the sum. Check: F = 6, and JOY = 10 + 15 + 25 = 50. So

\[ \begin{aligned} \text{OBSERVE} &= 15 + 2 + 19 + 5 + 18 + 22 + 5 \\ &= 86 \end{aligned} \]

76, 66 and 56 are each 10 less than the next, the result of slips in adding up the seven letters.

Checking the given examples first (F = 6 confirms simple alphabet positions) is the quickest way to find the coding rule.

Answer: B

GOOD LUCK is written as IQQF NWEM.

Each letter moves two places forward in the alphabet: H to J, A to C, R to T, D to F gives JCTF for HARD, and W to Y, O to Q, R to T, K to M gives YQTM for WORK. In PAYS the P, A and S follow the same rule (R, C, U).

Applying +2 to GOOD LUCK: G to I, O to Q, O to Q, D to F gives IQQF, and L to N, U to W, C to E, K to M gives NWEM. Options with IQQU shift D wrongly, and those ending in Q shift K wrongly.

Answer: D

The answer is None of these.

In EAGER = 51759 each letter is replaced by its alphabet position, and a two-digit position is reduced to the sum of its digits: E = 5, A = 1, G = 7, E = 5, R = 18, and 1 + 8 = 9.

The same rule gives CADET as C = 3, A = 1, D = 4, E = 5, T = 20 (2 + 0 = 2), that is 31452. None of 31547, 34157 or 31457 matches.

Answer: C

NORTH is written as GSQNM.

The code reverses the word and then moves every letter one place back in the alphabet. HEALTH reversed is H T L A E H, and one step back gives G S K Z D G (A moves back to Z), which matches the given code.

Applying the same rule, NORTH reversed is H T R O N, and one step back gives G S Q N M.

PRMFL, SPIUO and ISPUO come from shifting the letters forward or keeping the original order; none follows both steps of the rule.

Answer: B

DELHI is related to CDKGH.

Each letter of MUMBAI moves one place back in the alphabet: M to L, U to T, M to L, B to A, A to Z, I to H, giving LTLAZH.

The same rule turns D E L H I into C D K G H.

HILED simply reverses the word, BCKGH moves the first two letters back by two instead of one, and CDGKG changes the order of the middle letters, so none keeps the one-step-back rule for every letter.

Answer: C

A possible decode of YZXP is BACK.

The code replaces each letter by its mirror image in the alphabet, the letter the same distance from the other end: A and Z, B and Y, C and X, and so on, so that the positions of each pair add up to 27. Checking CABLE: C to X, A to Z, B to Y, L to O and E to V gives XZYOV, as stated.

Decoding YZXP the same way: Y to B, Z to A, X to C and P to K, which spells BACK. BABY would be coded YZYB, CELL as XVOO and BELL as YVOO, none of which is YZXP.

Answer: C

GATE is coded as 5247.

Each letter has its own fixed digit. From GIVE = 5137: G = 5, I = 1, V = 3, E = 7. From BAT = 924: B = 9, A = 2, T = 4.

So GATE = G, A, T, E = 5, 2, 4, 7, which is 5247.

The other options use the same four digits in the wrong order: 5427 swaps A and T, 5724 puts E second, and 2547 starts with A instead of G.

Such questions test whether each letter keeps the same digit wherever it appears; every letter of GATE also occurs in GIVE or BAT, so no guessing is needed.

Answer: A

The code for JUMPER is 312923.

The letters are taken in pairs and the alphabet positions of each pair are added: WAITER gives W + A = 23 + 1 = 24, I + T = 9 + 20 = 29, E + R = 5 + 18 = 23, that is 24 29 23.

For JUMPER: J + U = 10 + 21 = 31, M + P = 13 + 16 = 29, E + R = 23, giving 312923. Option (b) has 26 for MP, (c) has 30 for JU, and (d) keeps 25 at the start.

Answer: A

'Habit' is vog.

Compare sentences that share a word. 'Harmful' is in the first two sentences, and 'nat' is the code word they share, so nat = harmful. 'Avoid' is in the second and third, which share 'bor', so bor = avoid.

The second sentence, 'vog bor nat' = 'Avoid harmful habits', then leaves vog for habits. (bis means smoking, shared by the first and third sentences.)

Answer: A

BOOK is coded as 2662.

Each letter is replaced by its alphabet position, and a two-digit position is reduced to the sum of its digits: T = 20 gives 2, E = 5, A = 1, C = 3, H = 8, E = 5, and R = 18 gives 9, which is 2513859.

For BOOK: B = 2, O = 15 gives 6, O gives 6, and K = 11 gives 2, so the code is 2662. The other options do not follow this rule for O and K.