In this letter analogy question, ZY is related to CD, so you must select the pair of letters that stands in the same relationship to SR from the given alternatives.

Introduction / Context:

This question requires you to identify a symmetrical pattern in alphabet positions. The pair "ZY : CD" involves letters near the end of the alphabet mapped to letters near the beginning. Your task is to find the same kind of mapping for the pair "SR" from the given alternatives. Such questions test whether you can recognise hidden numerical relationships between letter positions.

Given Data / Assumptions:

- First pair: ZY and CD.
- Second pair to complete: SR and ?.
- Alphabet positions: A = 1, B = 2, ..., Z = 26.
- Options are RS, JK, JP, PQ and LM.
- The transformation used for both letters in ZY must be applied consistently to S and R.

Concept / Approach:

The key idea is to look for complementary positions in the alphabet. When we convert ZY to CD, we notice that Z and C are symmetric about a certain central value, and the same is true for Y and D. Specifically, if we add the position numbers of each pair of corresponding letters, the sum is constant. We can use this property to find the letters that pair with S and R.

Step-by-Step Solution:

Verification / Alternative check:

We can verify by checking sums again. For S (19) and J (10), 19 + 10 = 29. For R (18) and K (11), 18 + 11 = 29. The pattern is exactly the same as for ZY to CD. Now examine the options. Only the pair JK gives both sums equal to 29. Other options either do not use the correct positions or break the constancy of the sum. Therefore, JK is the only pair fully consistent with the rule discovered from the first analogy.

Why Other Options Are Wrong:

RS simply repeats the letters and does not produce complementary pairs; the sums would be 19 + 18, which does not match the required pattern.

JP would give sums 19 + 10 and 18 + 16, which are different and do not match the constant total of 29 seen in the first pair.

PQ would produce 19 + 16 and 18 + 17, again failing to give a consistent fixed sum for both positions.

LM similarly does not produce the constant-sum property observed in ZY and CD, so it cannot be the correct match.

Common Pitfalls:

Many candidates try to find a simple shift such as adding or subtracting a fixed number of positions, which does not always work for symmetrical analogies. Another error is to look only at one letter of the pair and ignore whether the same rule applies to the second letter. Symmetry questions require checking all letters and ensuring that the same numeric relationship holds throughout.

Final Answer:

Using the complementary-to-29 mapping, "SR" converts to JK.