Order and Ranking
About 6 min · Reasoning Ability · English
Time worked out from the lesson's 433 words at 150 words a minute, plus a minute for each question.
The concept is simple: determine the position of a person or object in a sequence based on given conditions. Questions involve rankings from top/bottom in a class, left/right in a row, or age-based ordering among a group.
Key ideas
- Position from opposite ends: If you know a person's rank from one end, you can find their rank from the other using the total count. This relationship is the backbone of almost every question.
- Total count determination: When two different positions of the same person are given (from top and bottom, or left and right), add them and subtract 1 to get the total.
- Positions between two people: The number of persons between two ranks equals the difference of their positions minus 1. For one person ranked from both ends, Total = Sum of positions from opposite ends − 1.
- Position after interchange: When two people exchange positions, their ranks swap but the total remains unchanged. Track carefully whose position is asked after the swap.
- Age-based ranking: Age ordering follows the same logic—oldest = rank 1 from top, youngest = rank 1 from bottom. Convert age comparisons to position comparisons.
Watch out for
- Forgetting the "−1" in the total formula → When you add positions from both ends, you count the person twice. Always subtract 1 to correct this.
- Confusing "from left" with "from right" after interchange → After a position swap, the row total stays same. Recalculate the new position from the asked direction carefully.
- Adding instead of subtracting for "between" calculation → Persons between = Difference of positions − 1, not sum. If A is 5th and B is 12th from left, there are 6 persons between them, not 16.
Quick reference
- Position from other end = Total − Given position + 1
- Total (same person, both ends known) = Top rank + Bottom rank − 1
- Persons between = |Rank₁ − Rank₂| − 1 (same end)
- After interchange: person takes the other's position, total unchanged
- Age ranking: Oldest = Rank 1 from top; Youngest = Rank 1 from bottom
Check yourself: 3 questions
1. In a row of 40 students, Rahul is 16th from the left end. What is his position from the right end?
2. In a class of 45 students, Priya ranks 12th from the top. Five students failed the exam and their ranks are not considered. What is Priya's rank from the bottom among the students who passed?
3. Among five friends A, B, C, D and E, A is older than B but younger than C. D is older than E but younger than B. Who is the youngest?
This lesson is cut from the topic's note, not rewritten. Fact-checked on 21 Oct 2026: an AI-assisted check of this note against cited sources; the errors it found were corrected that day. Some errors may remain. The questions are from Shishya's validated question bank.
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