Difficulty: Easy
Correct Answer: CJI
Explanation:
Introduction / Context:
This coding-decoding question uses a simple backward shift in the alphabet. We are told how the word BOULDER becomes ZMSJBCP, and our task is to find the coded form of ELK under the same transformation. Recognising a constant shift is the key idea here.
Given Data / Assumptions:
Concept / Approach:
We compare each letter of BOULDER with its coded counterpart and determine how much it has shifted. If the shift is consistent, we can apply it to each letter of ELK. From the mapping, every letter is shifted two positions backward, so we use that rule for the new word.
Step-by-Step Solution:
List letters: B O U L D E R → Z M S J B C P.
Check positions: B (2) to Z (26) is a -2 shift modulo 26.
O (15) to M (13) is -2, U (21) to S (19) is -2, L (12) to J (10) is -2, and so on.
Thus the rule is: each letter is moved two positions back in the alphabet.
Now apply the same rule to ELK.
E (5) shifted back two letters becomes C (3).
L (12) shifted back two letters becomes J (10).
K (11) shifted back two letters becomes I (9).
So ELK is coded as CJI.
Verification / Alternative check:
We can double-check by reversing the process: shifting C, J and I forward by two positions yields E, L and K respectively. This confirms that the code CJI correctly represents ELK under the same transformation used for BOULDER.
Why Other Options Are Wrong:
Options XIG, EOC and BXM do not arise from a uniform backward shift of two letters. They either move letters in the wrong direction or by different amounts, so they do not match the code pattern demonstrated by BOULDER → ZMSJBCP.
Common Pitfalls:
Some learners try uneven shifts or mistakenly shift forward instead of backward. Remember that in this scheme, every letter moves by the same amount, and checking at least three or four letter pairs is a good way to confirm the pattern.
Final Answer:
Using the same backward shift rule, ELK is coded as CJI.
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