UPSC Prelims 2024 CSAT Paper II · Q77 of 79 Logical Reasoning medium

If in a certain code, 'ABCD' is written as 24 and 'EFGH' is written as 1680, then how is 'IJKL' written in that code?

  1. (a) 11880 ✓ UPSC's answer
  2. (b) 11240
  3. (c) 7920
  4. (d) 5940

Why the answer is (a)

• Identify the position of each letter in the English alphabet: A=1, B=2, C=3, D=4; E=5, F=6, G=7, H=8; I=9, J=10, K=11, L=12.

• Verify the coding pattern using the first example: The code for 'ABCD' is the product of their positions, 1 × 2 × 3 × 4 = 24.

• Verify the pattern with the second example: The code for 'EFGH' is the product of their positions, 5 × 6 × 7 × 8 = 1680.

• Apply the established pattern to 'IJKL' by multiplying the positions of its letters: 9 × 10 × 11 × 12.

• Calculate the final product: 9 × 10 = 90, 90 × 11 = 990, and 990 × 12 = 11880.

• Therefore, the code for 'IJKL' is 11880, which corresponds to option (a).

Why the other options are wrong

(b) 11240
11240 is incorrect because it does not equal the product of the positions of I, J, K, and L (9 × 10 × 11 × 12).
(c) 7920
7920 is incorrect because it is the product of 8 × 9 × 10 × 11, which corresponds to the letters H, I, J, K, not I, J, K, L.
(d) 5940
5940 is incorrect because it is the product of 9 × 10 × 11 × 6, which does not match the sequential positions of the letters in 'IJKL'.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2024, held on 16 June 2024. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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