UPSC Prelims 2025 CSAT Paper II · Q67 of 78 Logical Reasoning medium

If FRANCE is coded as 654321 and GERMANY is coded as 9158437, then how is YEMEN coded ?

  1. (a) 54321
  2. (b) 81913
  3. (c) 71913
  4. (d) 71813 ✓ UPSC's answer

Why the answer is (d)

• Analyze the code for FRANCE (654321): F=6, R=5, A=4, N=3, C=2, E=1. This establishes a mapping where the 6th letter of the word maps to 6, the 5th to 5, and so on, down to the 1st letter mapping to 1. However, looking at GERMANY (9158437), G=9, E=1, R=5, M=8, A=4, N=3, Y=7.

• Comparing the two, the mapping is not based on position in the word, but rather a fixed substitution cipher for each letter.

• From FRANCE: F=6, R=5, A=4, N=3, C=2, E=1.

• From GERMANY: G=9, E=1, R=5, M=8, A=4, N=3, Y=7.

• The consistent values are: A=4, E=1, N=3, R=5.

• New values from GERMANY: G=9, M=8, Y=7.

• To code YEMEN: Y=7, E=1, M=8, E=1, N=3.

• Combining these gives 71813, which corresponds to option (d).

Why the other options are wrong

(a) 54321
Option (a) 54321 does not match the derived letter values for Y, E, M, E, N.
(b) 81913
Option (b) 81913 incorrectly assigns M=8 as the first digit and uses 9 for E, which is actually G's value.
(c) 71913
Option (c) 71913 incorrectly assigns 9 to the second letter E, whereas E is consistently coded as 1.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2025, held on 25 May 2025. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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