Coding-Decoding Questions and Answers

Answer: B

The code word for 7239 is GATE. From the two examples, 7 = G, 5 = I, 1 = V, 9 = E (from 7519 = GIVE), and 8 = C, 2 = A, 3 = T (from 823 = CAT). So 7239 becomes G, A, T, E, which reads GATE. VATE uses V for 7, which stands for the digit 1; EAVT and CEAT also use letters that belong to other digits. Only GATE uses the letters matched to 7, 2, 3 and 9 in that order. The code reads digit for digit: the digits of 7519 are placed against G, I, V and E, and those of 823 against C, A and T. Putting together the letters for 7, 2, 3 and 9 gives the new word without needing any other information.

Answer: A

In ACCURACY, each letter is first replaced by its opposite letter in the alphabet (A with Z, B with Y and so on), and then the letters are swapped in pairs. ACCURACY becomes ZXXFIZXB by the opposite letters, and swapping each pair gives XZFXZIBX, which is the given code.

For CONFUSED, the opposite letters are X L M U F H V W. Swapping each adjacent pair gives L X U M H F W V, that is LXUMHFWV. The other options are not formed by this rule: XLMUFHVW has the opposite letters without the swap, and WVHFUMLX and VWFHMUXL are reversals of the other forms.

Answer: C

In ABLE, the word is first reversed to ELBA, and then 1, 2, 3 and 4 are added to the letters in order: E+1 = F, L+2 = N, B+3 = E, A+4 = E, which gives FNEE as in the question.

Applying the same rule to QUIT: the reverse is TIUQ, and then T+1 = U, I+2 = K, U+3 = X, Q+4 = U. The code is UKXU. The options UXKU, KUXU and KUUX are made of the same letters in a different order and do not follow the rule.

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.