Coding-Decoding Questions and Answers

Answer: C

'Goals' is written as 5 or 7.

Compare the coded sentences word by word. 'Many' appears in the first two sentences, and the only common code is 9, so many = 9. 'Scored' appears in the first and third, and the only common code is 3, so scored = 3.

That leaves the codes 5 and 7 for the remaining words of the first sentence, 'how' and 'goals'. Neither word appears anywhere else, so there is no way to tell which code belongs to which. 'Goals' is therefore 5 or 7, and the options giving 5 alone or 7 alone claim more than the information shows; 'None of these' is wrong because one of the two codes is correct.

Answer: C

CLOCK is spelt as CMNCL.

Compare WATCH with WBSCI letter by letter:

The pattern of shifts is 0, +1, -1, 0, +1. Applying it to CLOCK: C stays C, L becomes M, O becomes N, C stays C, K becomes L, giving CMNCL.

The other options break the pattern: CKPCJ reverses every shift, CKNCJ moves L and K backwards instead of forwards, and CMNDJ changes the fourth letter, which should stay C, and moves K backwards.

Answer: B

'White' is coded as 4.

'256' (red colour chalk) and '254' (white colour chalk) share 2 and 5, which stand for 'colour' and 'chalk'. The digit that differs, 4 in place of 6, must stand for the word that differs, 'white' in place of 'red'.

'589' also contains 5 with 'colour', confirming that 5 is 'colour' and 2 is 'chalk'. 8 belongs to 'green' or 'flower'.

Coding-decoding questions like this are solved by comparing codes that share words: common words map to common digits.

Answer: C

FAMILY is coded as GBNJMZ.

Compare MOTHER with NPUIFS: M becomes N, O becomes P, T becomes U, H becomes I, E becomes F and R becomes S. Every letter moves one place forward in the alphabet.

Applying the same rule: F to G, A to B, M to N, I to J, L to M, Y to Z, giving GBNJMZ.

GNBJZM jumbles the order, GBNZMZ codes I as Z, and EBNJMX moves F and Y backwards.

Answer: C

We would drink fire.

We drink water, and in this code 'water' is called 'fire'. So the answer is the code name for water, which is fire.

'Water' is the real name, not the code. 'Sky' is the code for air, and 'earth' is the code for fire, so neither stands for water.

Answer: B

HIKM is written as 41.

The code is the sum of the alphabet positions of the letters:

\[ \begin{aligned} \text{ACEG} &= 1 + 3 + 5 + 7 = 16 \\ \text{DFGH} &= 4 + 6 + 7 + 8 = 25 \\ \text{HIKM} &= 8 + 9 + 11 + 13 = 41 \end{aligned} \]

36, 40 and 39 each come from miscounting one letter's position, for example taking K as 10 (40) or M as 11 (39).

Answer: B

DANCE = 27.

Each letter stands for its position in the alphabet: E = 5, and RED = 18 + 5 + 4 = 27. So

\[ \begin{aligned} DANCE &= 4 + 1 + 14 + 3 + 5 \\ &= 27 \end{aligned} \]

26 and 28 are one off, the result of mistaking the position of N or C, so 'None of these' is also wrong.

Answer: C

PREVIOUS is written QTHZJQXW.

In CUSTOMER → DWVXPOHV the letters move forward by 1, 2, 3, 4 and then repeat: C+1 = D, U+2 = W, S+3 = V, T+4 = X, O+1 = P, M+2 = O, E+3 = H, R+4 = V.

Applying the same shifts to PREVIOUS: P+1 = Q, R+2 = T, E+3 = H, V+4 = Z, I+1 = J, O+2 = Q, U+3 = X, S+4 = W, giving QTHZJQXW.

The other options start with O (a backward shift), have the wrong third letter (I) or contain nine letters.

Answer: C

23549 is written as ALGUT.

Match the digits with the letters position by position:

• 15789 = EGKPT gives 1 = E, 5 = G, 7 = K, 8 = P, 9 = T.
• 2346 = ALUR gives 2 = A, 3 = L, 4 = U, 6 = R.

So 2, 3, 5, 4, 9 become A, L, G, U, T, that is, ALGUT.

ALGTU swaps the last two letters, ALEUT uses E (the code for 1) for 5, and ALGRT uses R (the code for 6) for 4.

Answer: D

GATE is coded as 5247.

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

So G-A-T-E becomes 5-2-4-7, which is 5247.

All four options use the same four digits, so the order is what matters. 5427 swaps A and T, 5724 puts E's digit second, and 2574 starts with A's digit instead of G's.