Alphanumeric & Alphabet Series — IBPS PO Reasoning

An alphanumeric series is a string mixing letters, numbers and symbols — e.g. P 3 @ K 7 M % 2 R… — followed by quick questions: which element is third to the left of the seventh from the right, how many numbers are immediately followed by a symbol, and so on. These are 3–5 fast Prelims marks. The skill is not cleverness but careful condition-reading and clean counting, plus the EJOTY letter-position landmarks for the alphabet-based variants. Get the counting discipline right and these are 20-second wins.

1. What IBPS actually asks

• "Which element is Nth from the left/right?" — direct position counting.
• "Nth to the left of the Mth from the right" — a compound position (the classic).
• "How many numbers/letters/symbols are immediately preceded/followed by …?" — pattern-matching counts.
• Alphabet series: letter gaps, "which letter is Nth to the right of X", and word-based rearrangements (see also Coding–Decoding).

2. The compound-position rule (the classic question)

"3rd to the left of the 7th from the right" is done in two steps:

1. Find the anchor: the 7th from the right — count 7 in from the right end.
2. Move from the anchor: 3 positions to its left.

Do it in the stated order: locate the from-the-right/left reference first, then step the second count. A quick tip for a single string: "Nth to the left of Mth from the right" = (M + N)th from the right — but only verify with the actual string until the shortcut is second nature.

3. Counting "immediately preceded / followed by"

These are pattern-scans across the string:

• "A number immediately followed by a symbol" → scan for the pattern number, symbol (in that order) and count each occurrence.
• "Immediately preceded by" flips the order: symbol, number means the number is preceded by a symbol.
• Watch the boundary: the first element has nothing before it, the last has nothing after — they can't satisfy a "preceded/followed" condition on the missing side.

Read whether it's preceded (the thing comes before) or followed (the thing comes after). Swapping these is the single biggest error, and the two answers usually differ.

4. Alphabet series & EJOTY

For letter-position questions, anchor with the EJOTY landmarks so you never count from A:

E = 5, J = 10, O = 15, T = 20, Y = 25.

• "Which letter is 5th to the right of the 12th letter?" → 12th = L; 5 right = 17th = Q (O=15, +2).
• Opposite letter: position from the other end = 27 − position (A↔Z, B↔Y).
• Gap between letters: subtract their positions.

5. New-pattern variants

IBPS sometimes adds a rule layer: "if each symbol is dropped, which is 4th from the left?", or "after reversing the string, …". Apply the transformation to the string first (rewrite it), then answer normally. Never try to count on the original and the transformed string at once.

7. The protocol

1. Number the string lightly if it helps, or count carefully from the stated end.
2. Compound positions: find the "from-the-end" anchor first, then step the second count.
3. Preceded vs followed: confirm direction; scan for the exact ordered pattern; mind the boundaries.
4. Alphabet questions: anchor on EJOTY; use 27 − position for opposites.
5. Transformed strings: apply the rule to rewrite the string first, then answer.