Ranking & Order
Subject: Reasoning | Frequency: 1-2 questions per APPSC paper | Time: 30-45 sec/question
Introduction
Ranking questions involve positions in a row, class, or queue. You must find total count, convert rank from one end to another, or count people between two positions. The formula T = L + R - 1 (Total = rank from Left + rank from Right - 1) is the single most important formula and solves 80%+ of ranking questions.
Core Method
- Identify what's given — rank from top/left, rank from bottom/right, total
- Identify what's asked — convert, count between, find total
- Apply the appropriate formula
- Check for overlap — when two positions are given, verify they could be the same or different person
- Verify — answer must be a positive integer
Key Formulas
| Formula | Usage |
|---|---|
| Total = Left + Right - 1 | Find total from two positions of same person |
| Position from other end = Total - Position + 1 | Convert rank from one end to other |
| People between (non-overlap) = Total - Pos1 - Pos2 | When positions from opposite ends |
| People between (overlap) = Pos1 + Pos2 - Total - 2 | When positions overlap |
Worked Examples — Easy
Q1: In a class of 46 students, Anita ranks 12th from top. What is her rank from bottom?
- Rank from bottom = Total - Rank from top + 1
- = 46 - 12 + 1 = 35th
Q2: Rakesh ranks 7th from top and 28th from bottom. How many students in class?
- Total = 7 + 28 - 1 = 34 students
Q3: In a row of 40 children, Manu is 13th from the left. Position from right?
- Position from right = 40 - 13 + 1 = 28th
Worked Examples — Medium
Q4: Ravi is 7 ranks ahead of Sumit in a class of 39. Sumit is 17th from last. Ravi's rank from start?
- Sumit's rank from start = 39 - 17 + 1 = 23rd
- "7 ranks ahead" = lower rank number = 23 - 7 = 16th from start
Q5: Shilpa is 8th from left, Reena is 17th from right. After interchange, Shilpa becomes 14th from left. Total girls?
- After interchange: Shilpa now at Reena's original position
- Shilpa's new position from left = 14
- Reena's original position from right = 17
- Total = 14 + 17 - 1 = 30 girls
Q6: Mohan is 15th from left. Sohan is 20th from right. 8 people between them. Total? (non-overlapping)
- Total = 15 + 20 + 8 = 43
- (Alternative if overlapping: 15 + 20 - 8 - 2 = 25 — check which answer appears in options)
Worked Examples — Hard
Q7: Manish ranks 16th from top and 29th from bottom among passed students. 6 boys didn't participate; 5 failed. Total boys in class?
- Passed = 16 + 29 - 1 = 44
- Total = Passed + Failed + Non-participants = 44 + 5 + 6 = 55
Q8: Five friends: Mohan older than Prabir. Suresh younger than Prabir. Mihir older than Suresh but younger than Prabir. Ram is youngest.
- Order (oldest to youngest): Mohan > Prabir > Mihir > Suresh > Ram
- Middle position: Mihir
Q9: In a row of 50 people, A is 20th from left, B is 30th from right. People between A and B?
- B from left = 50 - 30 + 1 = 21
- A at 20, B at 21 → adjacent
- People between = 0
Shortcuts & Tricks
| Shortcut | When to Use |
|---|---|
| T = L + R - 1 | Most-used formula; memorize it cold |
| Position conversion | Other end = Total - This end + 1 |
| Interchange trick | New position from left = other person's old position from left |
| "Ahead" = lower number | "5 ranks ahead" means subtract 5 from rank |
| Between (non-overlap) | Between = Total - sum of both positions |
| Draw number line | For complex problems, mark positions on a line |
Common Mistakes
- Forgetting the -1 — Total = Top + Bottom - 1 (not just Top + Bottom)
- "Ahead" direction — "7 ranks ahead" from position 23 = position 16 (subtract, not add)
- Overlap vs non-overlap — must check if two people's positions overlap or not
- Mixing left-right with top-bottom — same formulas apply, but keep terminology consistent
- Not checking integer results — if the answer isn't a whole number, recheck your setup
Exam Strategy
- Memorize T = L + R - 1 and position conversion — these two solve 80%+ of questions
- APPSC keeps difficulty at easy-to-medium
- Time: 30-45 seconds per question
- For "between" questions, always check if two people could be the same person (overlap)
- Negative marking: -0.333 — formula-based questions give very high confidence
Practice Questions
- Class of 30, Rani is 10th from top. Rank from bottom? → 30 - 10 + 1 = 21st
- 5th from left and 18th from right. Total? → 5 + 18 - 1 = 22
- Class of 45, 12th from top and 26th from bottom. Same person? → 12 + 26 - 1 = 37 (not 45, so different person)
- A is 15th from left in row of 50. B is 20th from right. Between them? → B from left = 31. Between = 31 - 15 - 1 = 15
- Rank from top = 3x rank from bottom, total = 61. Rank from bottom? → 3x + x - 1 = 61, 4x = 62, x = 15.5 (not integer → check question)
Key Terms / Formulas
| Term | Meaning |
|---|---|
| T = L + R - 1 | Total = position from left + position from right - 1 |
| Position conversion | Other end = Total - This end + 1 |
| "Ahead" / "Before" | Lower rank number (closer to top/front) |
| "Behind" / "After" | Higher rank number (closer to bottom/back) |
| Overlap | When sum of two positions from opposite ends < Total + 1 |
| Non-overlap | When sum of two positions from opposite ends > Total + 1 |