Position-based letter shift rule: If “MOUSE” is coded as “PRUQC” by applying +3 to the first two letters, leaving the middle unchanged, and −2 to the last two letters, how is “SHIFT” written?

Difficulty: Medium

Correct Answer: VKIDR

Explanation:


Introduction / Context:
In many coding-decoding questions, a fixed positional rule (different shifts for different positions) is applied to each letter of a word. The example “MOUSE → PRUQC” hints at a specific positional transform rather than a single uniform Caesar shift. We must infer that transform and then encode “SHIFT”.


Given Data / Assumptions:

  • Alphabet indexing assumed cyclic (after Z wraps to A).
  • Example: MOUSE → PRUQC.
  • Target: SHIFT → ?


Concept / Approach:
Compare letters by position. For “MOUSE”: M→P (+3), O→R (+3), U→U (0), S→Q (−2), E→C (−2). This reveals a clean rule for a 5-letter word: +3 on the first two letters, keep the third unchanged, −2 on the last two letters.


Step-by-Step Solution:

Apply to S H I F T.First two (+3): S→V, H→K.Middle unchanged: I→I.Last two (−2): F→D, T→R.Result: VKIDR.


Verification / Alternative check:
If we attempted a single Caesar shift, MOUSE would not map to PRUQC because U would not remain U while M and O both increase. The positional rule uniquely explains all five mapped letters.


Why Other Options Are Wrong:

  • VJIDR / VIKRD / RKIVD: Each violates the derived position-wise rule at one or more positions (wrong shift for H or incorrect treatment of the middle letter).
  • None of these: Incorrect because VKIDR fits exactly.


Common Pitfalls:
Assuming a uniform shift for the whole word or overlooking that U remained unchanged in the exemplar, which is the key to spotting the middle-letter rule.


Final Answer:
VKIDR

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion