What Is an Alphanumeric Series?
An alphanumeric series is a single row of letters, digits and symbols, for example R 4 % T 7 K @ 2. Bank exams give one such row and ask 3–5 questions: which element sits at a given position, how many symbols are followed by a number, what changes if some elements are removed or reversed. It appears in IBPS and SBI Clerk prelims and mains, RRB Clerk and PO, and in SSC CGL/CHSL as letter-number series.
Key takeaway: Number the positions once (write small numbers under the series). Then use two formulas: k-th from the right = (total − k + 1)-th from the left, and "m to the left of position p" = position p − m. Count "immediately followed by" pairs by scanning left to right only once per question.
All 10 answers below were computed with a short Python script on the same series, so you can check your own counting against them.
Alphanumeric Series Formulas (Left and Right Positions)
| Question wording | Position from the left |
|---|---|
| k-th from the left | k |
| k-th from the right | total − k + 1 |
| m-th to the left of the k-th from the left | k − m |
| m-th to the right of the k-th from the left | k + m |
| m-th to the left of the k-th from the right | (total − k + 1) − m |
| Middle of positions a and b | (a + b) ÷ 2 (only if a + b is even) |
Direction rule: "to the left" means towards the start of the series, "to the right" means towards the end. This never changes in alphanumeric series questions.
Alphanumeric Series Questions with Answers (IBPS and SBI Clerk Pattern)
Use this series for all questions (24 elements: 10 letters, 8 digits, 6 symbols):
R 4 % T 7 K @ 2 B M # 9 E 3 £ U H 5 & Q 1 * D 8
| Position | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Element | R | 4 | % | T | 7 | K | @ | 2 | B | M | # | 9 |
| Position | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Element | E | 3 | £ | U | H | 5 | & | Q | 1 | * | D | 8 |
- How many symbols are immediately followed by a number? Pairs: @ 2 and # 9. Answer: 2.
- Which element is 7th to the left of the 16th element from the left? 16th is U; 16 − 7 = 9th = B.
- If all symbols are removed, which element is 5th from the right? New series: R 4 T 7 K 2 B M 9 E 3 U H 5 Q 1 D 8 (18 elements). 5th from the right = 5.
- How many numbers are immediately preceded by a letter and immediately followed by a symbol? R 4 %, E 3 £, H 5 &, Q 1 *. Answer: 4.
- How many letters are immediately followed by another letter? B M and U H. Answer: 2.
- Which element is exactly in the middle of the 5th element from the left and the 8th element from the right? 5th from left = position 5; 8th from right = 24 − 8 + 1 = 17. Middle = (5 + 17) ÷ 2 = 11th = #.
- How many vowels are there in the series? E and U. Answer: 2.
- If the first 12 elements are written in reverse order, which element will be 8th from the left? New start: 9 # M B 2 @ K 7 … so the 8th element is 7.
- How many numbers are immediately preceded by a symbol and immediately followed by a letter? @ 2 B and # 9 E. Answer: 2.
- Which element is 4th to the right of the 10th element from the right? 10th from right = 24 − 10 + 1 = 15th (£); 15 + 4 = 19th = &.
Tricks for Alphanumeric Series in Bank Exams
- Write position numbers under every 5th element (5, 10, 15, 20). It cuts counting errors in half.
- Convert everything to "from the left" before adding or subtracting.
- For "immediately preceded by X and followed by Y", scan only the middle type (for example only numbers) and look one step left and right.
- Removal questions: rewrite the shortened series fully. Positions change after removal.
- Reversal questions: only the reversed block changes; elements after it keep their positions.
- Group-pattern questions (for example "R % : T K : ?") pair an element with the one 2 places to its right, and each new group starts 3 places later (positions 1 and 3, then 4 and 6), so the answer is @ B (positions 7 and 9).
Common Mistakes in Alphanumeric Series
- Using total − k instead of total − k + 1 for positions from the right.
- Counting the starting element when moving "m to the left".
- Treating £ or # as a letter, or a letter O as the digit 0. Read the series slowly once.
- Answering a removal question on the original series.
Alphanumeric Series Practice Questions (Same Series)
- How many digits are in the series? Answer: 8.
- Which element is 6th from the right? Answer: & (24 − 6 + 1 = 19th from the left).
- How many letters are immediately followed by a symbol? Answer: 2 (K @ and M #).
- Which element is 3rd to the left of the 9th element from the right? Answer: E (9th from the right = 24 − 9 + 1 = 16th from the left; 16 − 3 = 13th).
Alphanumeric Series FAQs
What is an alphanumeric series in reasoning?
It is a row of letters, numbers and symbols on which questions ask about positions, adjacent pairs, and changes after removing or reversing elements.
How do you solve alphanumeric series questions quickly?
Number the positions once, convert every "from the right" position to "from the left" with total − k + 1, and scan the series only once per counting question.
Are alphanumeric series asked in SBI Clerk prelims?
Yes. SBI Clerk and IBPS Clerk prelims often have a 3–5 question alphanumeric series set; SBI PO and IBPS PO ask it less often, sometimes mixed with coding.
What is the formula for position from the right?
Position from the right = total − position from the left + 1.
How many questions come from alphanumeric series?
Usually one set of 3 to 5 questions in clerk-level reasoning sections.
Practice Next
- Mock tests: IBPS Clerk Inequality, Syllogism and Alphanumeric Series Test 01, SBI Clerk Inequality, Syllogism and Alphanumeric Series Test 01, IBPS PO Inequality, Syllogism and Alphanumeric Series Test 01 and SSC CHSL Number and Alphabet Series Mock Test 01.
- Related notes: order and ranking questions for bank exams, missing number series tricks for bank exams, wrong number series for bank exams and input output reasoning for SBI PO, plus coding decoding tricks for SSC CGL.
- Browse all study notes.