Alphabet Series — Next Letter with Growing Steps Complete the sequence: H, I, K, N, ?

Introduction / Context:
Alphabet series with single letters often advance by step sizes that increase by 1 each time. Detecting the incremental jump (+1, +2, +3, …) determines the next letter quickly.

Given Data / Assumptions:

• Sequence: H, I, K, N, ?
• Indexing: A=1, ..., Z=26.
• Assume increasing step sizes.

Concept / Approach:
Compute the jumps between successive letters and extrapolate the next jump by adding 1 to the previous step size.

Step-by-Step Solution:
H(8) → I(9): +1I(9) → K(11): +2K(11) → N(14): +3Next step should be +4.N(14) + 4 = 18 → R.

Verification / Alternative check:
The pattern of step sizes (1, 2, 3, 4) is strictly increasing by 1, confirming R uniquely.

Why Other Options Are Wrong:

• O (15), Q (17), S (19): These represent +1, +3, or +5 from N, not the required +4.

Common Pitfalls:
Assuming constant differences or skipping the check on step-size growth. Always list numeric indices to avoid miscounting letter gaps.

Final Answer:
R