In this number analogy, 236 is related to 472. Using the same pattern, which number should complete the analogy 236 : 472 :: 123 : ?

Introduction / Context:
This question checks the ability to identify a direct arithmetic relationship between two numbers and use it to determine a corresponding number in the second pair. Number analogy questions like this often use simple operations such as multiplication, division, or addition of a constant, and they are fundamental in many aptitude tests.

Given Data / Assumptions:
First pair: 236 : 472. Second pair: 123 : ?. We must assume basic arithmetic operations unless there is clear evidence of a more complex pattern. Exactly one option must satisfy the same transformation.

Concept / Approach:
The most natural step is to see whether 472 is a simple multiple or sum of 236. If this fails, we can then analyse digit wise relationships. In this case, a quick multiplication check shows that 236 multiplied by 2 yields 472, which indicates a straightforward linear relation. Applying the same operation to 123 will produce the corresponding number in the second pair.

Step-by-Step Solution:
Step 1: Check for multiplication or division. Compute 236 * 2. 236 * 2 = 472. Step 2: Interpret the relationship. The second number is exactly double the first number. Step 3: Apply the same operation to 123. 123 * 2 = 246. Step 4: Match the result with the options. 246 appears as option A and so is the candidate answer.

Verification / Alternative check:
We can verify by seeing whether any other option might tempt a wrong pattern. For instance, 426, 642, or 247 do not equal 2 times 123. Specifically, 426 / 123 is not equal to 2, 642 / 123 is not equal to 2, and 247 is only 124 units more than 123, which does not mirror the behavior of the first pair. There is no consistent ratio or difference with those values that matches the first transformation of exactly doubling 236. Therefore only 246 satisfies the rule.

Why Other Options Are Wrong:
426 is not equal to 2 times 123 and does not maintain the same multiplicative factor observed between 236 and 472. 642 is larger than 246 and does not correspond to any simple multiple of 123 that mirrors the earlier pair. 247 is just 124 units greater than 123 and does not reflect a doubling operation. 234 is slightly less than 2 times 117 and is unrelated to the transformation 236 to 472.

Common Pitfalls:
Test takers sometimes rush into digit wise additions or reversals and ignore simple whole number multiplication. Another mistake is to assume that the second pair will always use a different or more complicated pattern, whereas exam setters usually maintain the same transform. Always begin with straightforward checks such as doubling, halving, or adding a constant, and only move to complex rules if those fail. This saves time and improves accuracy.

Final Answer:
The number that correctly completes the analogy is 246.