Coding-Decoding Questions and Answers

Answer: A

V is coded as 1331.

X is the 24th letter and 1728 = 12³; T is the 20th letter and 1000 = 10³. In both cases the number is the cube of half the position of the letter (24/2 = 12 and 20/2 = 10). V is the 22nd letter, so its code is the cube of 11, which is 1331.

1464, 1672 and 1286 are not perfect cubes, so they cannot follow the rule.

Check with the letter T: it is the 20th letter, half of 20 is 10 and 10³ is 1000, which is the given code. Check with X: it is the 24th letter, half of 24 is 12 and 12³ is 1728, the other given code. The rule works for both, so it applies to V as well.

Answer: A

CHANGE is written as DIBOHF.

In LIGHT to MJHIU each letter moves one step forward (L to M, I to J, G to H, H to I, T to U), and CRANE would follow the same rule. Applying it to CHANGE gives C to D, H to I, A to B, N to O, G to H and E to F, which is DIBOHF.

The other options change some of the letters by different amounts, so they do not follow the rule.

To avoid errors, shift each letter of CHANGE separately: C to D, H to I, A to B, N to O, G to H and E to F. Reading them together gives DIBOHF. The other options each contain at least one letter that is not the next letter of the original, for example EHBMIF changes C to E.

Answer: B

The code for pencil is 6.

'694' means pen, and, pencil and '3415' means pen, is, like, marker. The only common digit is 4, and the only common word is pen, so pen is 4. In '981' (rubber and marker) and '694' the common digit 9 matches the common word 'and'. So in '694', 9 is 'and', 4 is pen and the last digit 6 must be pencil.

4 is pen, 9 is 'and' and 1 belongs to rubber, marker or 'like' words, so those are not pencil.

Compare the codes in pairs. '694' and '981' share 9 and the word 'and' is common to both meanings, so 9 is 'and'. '694' and '3415' share 4 and the word 'pen', so 4 is pen. Only 6 is left in '694' and only 'pencil' is left in the meaning, so pencil is 6.

Answer: D

The relation is that the first two letters move two places forward and the last two letters move three places backward: S, D, F, G become U, F, C, D. Checking with GHUJ gives I, J, R, G, which is the given pair.

\[ K+2=M,\ O+2=Q,\ P-3=M,\ I-3=F \]

So KOPI is related to MQMF, the fourth option. IPMF, IQMF and MPNG each apply the rule to some letters wrongly.

Answer: D

BRIDGE is coded as 3#S9@2. Each letter keeps one symbol or digit throughout. BUILDING is 3 7 S 1 9 S 5 @, so B is 3, U is 7, I is S, L is 1, D is 9, N is 5 and G is @. RIVER is # S 6 2 #, so R is #, I is S, V is 6 and E is 2.

\[ B=3,\ R=\#,\ I=S,\ D=9,\ G=@,\ E=2 \]

Putting these together gives 3 # S 9 @ 2. The options ending in 6 use the code of V for E, and the option with 7 in the fourth place uses the code of U for D, so they do not match the two given words.

Answer: C

'Aftercare' could be tagazen.

Line the words up. All three contain 'taga', and all three English words contain 'care', so taga = care. Then relf = free, o = ful and fer = less. The coded words put the modifier first: carefree is relftaga, careful is otaga, careless is fertaga. So the code reverses the English order.

In 'aftercare', 'after' comes first and 'care' second, so the code must put 'taga' first followed by a new syllable for 'after': taga + zen = tagazen. 'Zentaga' keeps the English order, 'tagafer' reuses 'fer' (less), and 'relffer' contains no 'taga' at all.

Answer: B

The code for BEACH is IDBFC.

Find the rule from IMAGE → FHBNJ. Write IMAGE backwards, E G A M I, and move each letter one place forward in the alphabet: F H B N J. FIELD backwards is D L E I F, and one step forward gives E M F J G, matching the given code.

Apply the same rule to BEACH: backwards it is H C A E B, and one step forward gives I D B F C.

CEADP, JGIBC and IBCEC do not follow the reverse-and-shift rule; IBCEC, for example, starts correctly with I but then fails at the second letter, which must be C + 1 = D.

Answer: D

HIGH is coded as 19-23-17-19.

Each letter is replaced by the prime number at its alphabet position. C is the 3rd letter and the 3rd prime is 5; A gives the 1st prime 2; G the 7th prime 17; E the 5th prime 11. That reproduces 5-2-17-11 for CAGE, and HIDE gives the 8th, 9th, 4th and 5th primes, 19-23-7-11.

For HIGH: H is the 8th letter (19), I the 9th (23), G the 7th (17), H again 19. Of the other codes, 5-17-1-2 and 13-3-1-2 do not begin with H's code 19, and 17-19-13-17 uses the primes for G, H and F.

Answer: B

P* is P R T O Q S U.

Number the letters by their positions round the clock: O 0, P 1, Q 2, R 3, S 4, T 5, U 6, V 7, W 8, X 9, Y 10, Z 11.

• O* = O Q S Z P R T is positions 0, 2, 4, 11, 1, 3, 5.
• X* = X Z P W Y O Q is positions 9, 11, 1, 8, 10, 0, 2.

Both follow one rule: start at the letter, take the next two by steps of two, then go back one place from the start and again take three letters by steps of two. In offsets from the start: 0, +2, +4, -1, +1, +3, +5.

For P (position 1) this gives 1, 3, 5, 0, 2, 4, 6: P R T O Q S U. The other options do not keep the offsets: P U W ... starts with a step of five, and P S U ... with a step of three.

Answer: B

The answer is P R T O Q S U.

On the clock the letters run O, P, Q, ..., Z clockwise, one per hour mark. Read O* by steps around the clock: O, then +2 (Q), +4 (S), then one place behind O (Z), then +1 (P), +3 (R), +5 (T). X* follows the same rule from X: X, Z (+2), P (+4), W (-1), Y (+1), O (+3), Q (+5).

Applying it to P: P, R (+2), T (+4), O (-1), Q (+1), S (+3), U (+5), which gives P R T O Q S U.

P U W R T V X starts with a jump of 5; P T V Q S U W starts with a jump of 4; P S U P R T V repeats P and starts with a jump of 3. None follows the +2, +4, -1, +1, +3, +5 pattern.