What is the next letter in the given alphabetic series M, N, J, Q, G, ?

Introduction / Context:
This question presents a short alphabetic series and asks for the next letter. Such series often follow a pattern based on arithmetic progressions of alphabet positions, sometimes alternating between increases and decreases. Recognising the underlying numeric pattern is the key to solving these puzzles accurately and quickly.

Given Data / Assumptions:
- Series: M, N, J, Q, G, ?
- Alphabet positions: A=1, B=2, ..., Z=26.
- We assume a consistent numeric rule determines the jump from each term to the next.

Concept / Approach:
The strategy is to convert each letter to its numerical position and then examine the differences between successive terms. If a clear pattern emerges, we apply it to find the missing term. Often, such series alternate between adding and subtracting numbers with a regular change in magnitude. Observing that behaviour quickly leads to the solution.

Step-by-Step Solution:
Step 1: Convert letters to numbers: M=13, N=14, J=10, Q=17, G=7. Step 2: Calculate successive differences: from 13 to 14 is +1, from 14 to 10 is −4, from 10 to 17 is +7, from 17 to 7 is −10. Step 3: Observe the pattern in the absolute differences: 1, 4, 7, 10. They increase by 3 each time. Step 4: Also note that the signs alternate: +, −, +, −. Therefore, the next step should be +13 (continuing the pattern of adding 3 to the magnitude and reversing the sign). Step 5: Add 13 to the last value 7 (the position of G). This gives 7 + 13 = 20. Step 6: The 20th letter of the alphabet is T. Therefore, the next letter in the series is T.

Verification / Alternative check:
Extend the series with T and verify the pattern: positions become 13, 14, 10, 17, 7, 20. Differences are +1, −4, +7, −10, +13. The absolute differences remain 1, 4, 7, 10, 13, increasing by 3 each time, and the signs keep alternating. This confirms that T perfectly fits the established rule and that no other letter can satisfy the same pattern.

Why Other Options Are Wrong:
- "U" is 21, which would give a difference of +14 from 7, breaking the step size pattern.
- "S" is 19, giving +12, which does not maintain the consistent increase by 3 in absolute difference.
- "H" is 8, giving +1 from 7, which would reset the difference instead of continuing the series of growing gaps.
None of these options preserves both the alternating sign and the increasing difference sequence.

Common Pitfalls:
Some learners focus only on the visible letters and attempt to guess based on approximate positions. Others may spot only the alternating sign but ignore that the absolute difference also grows in a regular way. Writing down the numeric positions and computing each difference explicitly helps reveal the pattern clearly. This disciplined approach is useful for many similar alphabet series questions in reasoning exams.

Final Answer:
The correct next letter in the series M, N, J, Q, G is T.