Order, ranking and alphanumeric series for IBPS PO

Order and ranking questions have no hidden logic. They test whether you can count under time pressure without slipping by one. The aspirants who score here are not better at reasoning; they simply number positions before they count, and they write down which end they are counting from.

IBPS PO uses three forms: an alphanumeric series (letters, digits and symbols in a line), rank arithmetic (positions in a row or class), and comparison puzzles (who is heavier, taller or older than whom).

Alphanumeric series: number first

Write position numbers above the series before reading the first question. It takes 20 seconds and removes nearly every counting error.

The series used in this guide

K 5 @ R 8 T # 2 M E 7 $ P 3 & A 9 U 4 D

There are 20 elements: 9 letters, 7 digits and 4 symbols.

The two formulas

• nth from the right = position (total − n + 1) from the left.
• "k to the right of" position p = position p + k; "k to the left of" = position p − k.

Worked example 1: position questions

1. Which element is fourth to the right of the ninth element from the left?
   • Ninth from the left is M (position 9). Four to the right: position 13, P.
2. Which element is fifth to the left of the sixth element from the right?
   • Sixth from the right is position 20 − 6 + 1 = 15 (&). Five to the left: position 10, E.
3. If every symbol is removed, which element is eleventh from the left?
   • The new series is K 5 R 8 T 2 M E 7 P 3 A 9 U 4 D. Eleventh is 3.

Worked example 2: pattern-count questions

1. How many digits are immediately preceded by a letter?
   • Check each digit's left neighbour: K5, R8, E7, P3, A9, U4. Not 2 (after #). Six.
2. How many digits are immediately preceded by a letter and immediately followed by a letter?
   • R 8 T, A 9 U and U 4 D. Three.

Rank arithmetic

For a single person in a row or class:

Worked example 3: interchange

In a row, P is 10th from the left and Q is 15th from the right. They swap places, and P becomes 18th from the left. How many people are in the row?

• After the swap, P stands where Q stood.
• That spot is 18th from the left and 15th from the right.
• Total = 18 + 15 − 1 = 32.

Worked example 4: two possible totals

In a queue, A is 9th from the front and B is 6th from the back. There are exactly four people between A and B. What is the smallest possible number of people in the queue?

• If A is ahead of B: 9 (up to A) + 4 + 6 (B to the back) = 19.
• If B is ahead of A: B is 5 places in front of A, so B is 4th from the front. B is also 6th from the back, so the total is 4 + 6 − 1 = 9. Check: A is 9th, the last person, with positions 5 to 8 between them.
• Both are valid, so the minimum is 9 and the maximum is 19.

Worked example 5: a comparison puzzle

Five people, P, Q, R, S and T, have different weights.

1. Q is heavier than only two people.
2. S is heavier than Q, but S is not the heaviest.
3. R is heavier than S.
4. P is not the lightest.

Solving

• Clue 1: two people are lighter than Q, so Q is 3rd heaviest.
• Clue 2: S is 2nd.
• Clue 3: R is heavier than S, so R is 1st.
• P and T take 4th and 5th. Clue 4: P is 4th and T is the lightest.
• Order: R > S > Q > P > T.

Common mistakes

• Counting without numbering positions. One skipped element changes every answer after it.
• Mixing "to the right of" with "from the right".
• Removing elements and forgetting to renumber the new series.
• Missing the overlap case in "people between" questions.
• Misreading "heavier than only two". It means exactly two people are lighter, so the person is third lightest, not second.

Practice set

Use the series above for questions 1 to 4.

1. How many digits sit immediately between two letters?
2. Which element is seventh from the right?
3. How many symbols are immediately followed by a digit?
4. How many vowels are in the series?
5. In a class of 45, a student is 17th from the top. What is their rank from the bottom?
6. In a row, X is 7th from the left and Y is 12th from the right. They swap places, and X becomes 16th from the left. How many people are in the row?
7. In worked example 5, who is the second lightest?
8. In a row of 30, a candidate is 12th from the left. Another is 5 places to the candidate's right. What is the second person's position from the right?

Answers

1. Three: R 8 T, A 9 U and U 4 D.
2. 3. Position 20 − 7 + 1 = 14.
3. One: # 2. The other symbols (@, $, &) are each followed by a letter.
4. Three: E, A and U.
5. 29th. 45 − 17 + 1 = 29.
6. 27. X now stands in Y's old place: 16th from the left and 12th from the right, so 16 + 12 − 1.
7. P. The order is R, S, Q, P, T, so P is fourth heaviest and second lightest.
8. 14th. The second person is 17th from the left; 30 − 17 + 1 = 14.

What to do next

• Cover the answers and re-solve every question on the series above, timing yourself at under 40 seconds each.
• Practise one alphanumeric series and two ranking questions a day for a week, writing position numbers every time.
• Revise coding–decoding for symbol handling, and floor and box puzzles, where comparison clues often appear inside bigger sets.