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Coding and Decoding

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Question 41Question →

In a certain coding language, words are translated by shifting each letter forward in the English alphabet based on its positional index within the word. The first letter is shifted by one position, the second letter by two positions, the third letter by three positions, and so on. Based on this translation rule, match the given words on the left with their correctly coded equivalents on the right.

Click a left item, then click its matching right item

Items

STAR
WIND
LOCK
PUMP

Matches

Show answer & explanation

Answer

STAR matches with TVDV, WIND matches with XKQH, LOCK matches with MQFO, and PUMP matches with QWPT.
By successfully applying a variable forward shift (+1 for the first letter, +2 for the second, +3 for the third, and +4 for the fourth) to each original word, we generate their exact coded counterparts.

Step-by-Step Solution

1
Identify the core logic for the encryption method.
Each letter is shifted forward by its index position in the word (+1, +2, +3, +4).
This establishes the rule needed to decode or encode all the given words.
2
Apply the progressive shift to the word 'STAR'.
S(+1) = T, T(+2) = V, A(+3) = D, R(+4) = V. The encoded word is TVDV.
To accurately pair the first item.
3
Apply the progressive shift to the word 'WIND'.
W(+1) = X, I(+2) = K, N(+3) = Q, D(+4) = H. The encoded word is XKQH.
To accurately pair the second item.
4
Apply the progressive shift to the word 'LOCK'.
L(+1) = M, O(+2) = Q, C(+3) = F, K(+4) = O. The encoded word is MQFO.
To accurately pair the third item.
5
Apply the progressive shift to the word 'PUMP'.
P(+1) = Q, U(+2) = W, M(+3) = P, P(+4) = T. The encoded word is QWPT.
To accurately pair the final item.

Key Concept

Positional Letter Shifting
Question 42Question →

An autonomous delivery drone navigation system encodes geographic sector names into numerical strings for secure broadcasting. The sector name "DELTA" is transmitted as 46-44-30-14-52, and the sector name "BRAVO" is transmitted as 50-18-52-10-24. Based on this logic, which numerical string represents the sector name "EAGLE"?

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Answer: 44-52-40-30-44

Answer

The string 44-52-40-30-44 correctly represents the sector name EAGLE.
The correct answer accurately applies the coding logic: it determines the reverse alphabetical position of each letter (found by subtracting the forward position from 27) and multiplies that value by 2. For the word EAGLE: E is 5th, so its reverse is 22 (22 × 2 = 44). A is 1st, reverse is 26 (26 × 2 = 52). G is 7th, reverse is 20 (20 × 2 = 40). L is 12th, reverse is 15 (15 × 2 = 30). Combining these gives 44-52-40-30-44.

Step-by-Step Solution

1
Analyze the numerical values assigned to the letters in 'DELTA' and 'BRAVO' to find the base transformation.
D corresponds to 46, E to 44, L to 30, T to 14, and A to 52.
Identifying the relationship between the first few letters and their numerical outputs reveals the underlying logic.
2
Determine the mathematical rule applied to the alphabetical positions.
The forward position of D is 4. Its reverse position (27 - 4) is 23. Multiplying 23 by 2 gives 46. This logic holds for all letters.
A consistent pattern must be established that works for every letter in both provided examples.
3
Apply the established logic to the target word 'EAGLE'.
E (5) -> reverse 22 -> 44. A (1) -> reverse 26 -> 52. G (7) -> reverse 20 -> 40. L (12) -> reverse 15 -> 30. E (5) -> reverse 22 -> 44.
Applying the exact rule ensures the correct encryption of the target string.

Key Concept

Reverse Alphabetical Indexing and Mathematical Transformation
Estimated Time:1m 30s
Question 43Question →

A deep sea research submarine logs environmental phenomena in an encrypted transmission system. In this protocol, the phenomenon "TRENCH" is recorded as "VTDPEJ", and "CORAL" is recorded as "ENTZN". Based on this cryptographic pattern, what will be the recorded code for the word "TIDES"?

Show answer & explanation

Answer: VHFDU; vhfdu

Answer

VHFDU
The established coding pattern shifts consonants forward by 2 positions in the English alphabet and shifts vowels backward by 1 position. Applying this rule to 'TIDES', the consonants (T, D, S) become (V, F, U) and the vowels (I, E) become (H, D). Combining these letters in sequence yields 'VHFDU'.

Step-by-Step Solution

1
Analyze the letter shifts in the first example 'TRENCH' -> 'VTDPEJ'.
T(+2)=V, R(+2)=T, E(-1)=D, N(+2)=P, C(+2)=E, H(+2)=J. Consonants move forward by 2 positions, while the vowel 'E' moves backward by 1 position.
Identifying the initial transformation rule for different letter types.
2
Verify the identified pattern with the second example 'CORAL' -> 'ENTZN'.
C(+2)=E, O(-1)=N, R(+2)=T, A(-1)=Z, L(+2)=N. The pattern is confirmed: Consonants +2, Vowels -1.
Confirming the hypothesis to ensure the rule is universally applied in this cryptographic protocol.
3
Classify the letters of the target word 'TIDES' into vowels and consonants.
Consonants: T, D, S. Vowels: I, E.
Preparing to apply the appropriate shift rule to each letter.
4
Apply the verified shift rules (+2 for consonants, -1 for vowels) to 'TIDES'.
T(+2)=V, I(-1)=H, D(+2)=F, E(-1)=D, S(+2)=U. The final code is VHFDU.
Executing the final translation to obtain the required answer.

Key Concept

Coding and decoding using bifurcated shift rules for vowels and consonants
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