In the following alphanumeric series, find the next term: X24C, V22E, T20G, ?

Introduction / Context:
This question involves an alphanumeric series, where each term consists of a letter, a number and another letter. Such patterns commonly appear in reasoning tests to check your ability to recognise simultaneous progressions in different components of a term. Here, you must find a consistent rule that explains how the letters and numbers change across X24C, V22E and T20G, and then apply that rule to determine the missing term.

Given Data / Assumptions:

• Known terms: X24C, V22E and T20G.
• Each term has the form Letter Number Letter.
• The letters are from the English alphabet and are case insensitive.
• The numeric part decreases regularly from 24 to 22 to 20.
• The missing term must follow the same pattern and match one of the options.

Concept / Approach:
The key idea is to treat the positions of the letters in the alphabet as numbers and look for simple step patterns. The first letters may follow one arithmetic sequence, the numbers another, and the last letters yet another. Often, these sequences move by a constant difference. Once you identify those differences, you can extend each component one more step to generate the next term. Finally, you match this derived term with the options to select the correct one.

Step-by-Step Solution:
Write letter positions: X is 24, V is 22, T is 20 in the alphabet. First letters: 24, 22, 20 show a pattern of minus 2 each time, so the next should be 18, which is R. Numbers: 24, 22, 20 also reduce by 2 each step, so the next number is 18. Last letters: C is 3, E is 5, G is 7 in the alphabet, increasing by 2 each time, so the next should be 9, which is I. Combining all three components, the next term is R18I, which matches option C.

Verification / Alternative check:
Check the whole series with the discovered rule: X24C (24, 24, 3), V22E (22, 22, 5), T20G (20, 20, 7), R18I (18, 18, 9). In each step, the first letter and the number both decrease by 2, while the last letter increases by 2. The pattern stays perfectly consistent across all transitions. No other option respects all three simultaneous sequences, which confirms that the derived answer is unique and correct.

Why Other Options Are Wrong:
Option A, RI19, has letters that could fit the pattern but the number 19 does not follow the minus 2 rule. Option B, R19I, again breaks the numeric pattern since the number should be 18, not 19. Option D, RI18, places R and I in the correct positions but swaps their order, so it no longer fits the observed letter pattern. Option E, None of these, is incorrect because option C matches the exact pattern derived from the given terms.

Common Pitfalls:
A frequent mistake in such problems is to focus on only one component, such as the letters, and ignore mismatches in the numeric part, or vice versa. Some learners also miscount letter positions in the alphabet, especially near the end, which leads to incorrect predictions. To avoid these errors, always list alphabets with their positions and check every component of the term carefully before deciding on the next element in the series.

Final Answer:
The next term that continues the established pattern is R18I.