Reasoning : Logical Reasoning & Analytical Ability

Q 107 / 325

UPSC CSE Prelims 2021

In the English alphabet, the first 4 letters are written in opposite order; and the next 4 letters are written in opposite order and so on; and at the end Y and Z are interchanged.
Which will be the fourth letter to the right of the 13th letter?

EXPLANATION

Correct Option

The English alphabet is reordered according to the specified rules:

  • The first four letters are written in opposite order (D C B A). This pattern continues for subsequent blocks of four letters (e.g., E F G H becomes H G F E).
  • The letters Y and Z are interchanged (Z Y).

Applying these rules, the modified alphabetical series is constructed as follows:

D C B A (1-4)
H G F E (5-8)
L K J I (9-12)
P O N M (13-16)
T S R Q (17-20)
X W V U (21-24)
Z Y (25-26)

The question asks for the fourth letter to the right of the 13th letter. This position corresponds to the (13 + 4) = 17th letter in the modified sequence.

Counting the letters in the modified series up to the 17th position:

  1. D
  2. C
  3. B
  4. A
  5. H
  6. G
  7. F
  8. E
  9. L
  10. K
  11. J
  12. I
  13. P (13th letter)
  14. O
  15. N
  16. M
  17. T (17th letter)

Therefore, the 17th letter in the reordered alphabet is 'T'.

Incorrect Options:

  • N: In the modified series, 'N' is positioned as the 15th letter.

  • H: In the modified series, 'H' is positioned as the 5th letter.

  • I: In the modified series, 'I' is positioned as the 12th letter.

Explanation figure for the question: In the English alphabet, the first 4 letters are written in opposite order; and the next…