Introduction
Questions on rank-after-removal ask how a person's position changes when some members are removed from the line/class. These appear frequently in aptitude tests because they test careful counting - identifying who was removed (above or below) is the key.
Mastering this pattern lets you quickly update ranks when people leave or when additional members are inserted.
Pattern: Rank after Removal
Pattern
Key idea: Only removals of people ahead of the person change their rank - new_rank = old_rank - (number of removed people who were ahead).
Variants you must recognise:
- If x people who were ahead leave → new rank = old rank - x.
- If x people behind leave → rank remains the same.
- If removals are mixed (some ahead, some behind) → subtract only those who were ahead.
- If asked for new total strength, update total = old total - total removed.
Step-by-Step Example
Question
There are 40 students in a class. Ravi is 10th from the top. Five students who were ahead of him leave the class. What is Ravi’s new rank from the top?
Solution
-
Step 1: Identify original data
Total = 40; Ravi’s old rank from top = 10 → so 9 students were ahead of him. -
Step 2: Count how many ahead have left
Given: 5 students who were ahead of Ravi leave. -
Step 3: Apply the rule
New rank = Old rank - (number of removed people who were ahead) = 10 - 5 = 5. -
Final Answer:
Ravi’s new rank is 5th from the top. -
Quick Check:
Originally 9 ahead → after 5 of those leave, 4 remain ahead → Ravi becomes 4 + 1 = 5th ✅
Quick Variations
1. If students behind leave → rank unchanged (only total reduces).
2. If you are given removals but not whether they were ahead/behind, determine positions (e.g., list positions) or ask for conversion to check which side they were.
3. When multiple people leave including some ahead and some behind → subtract only the count of those ahead.
4. If asked the new rank from the bottom, convert: New position from bottom = New total - New rank from top + 1.
Trick to Always Use
- Step 1 → Convert the given rank to “people ahead” (people_ahead = rank - 1).
- Step 2 → Subtract the number of removed people who were ahead: new_people_ahead = people_ahead - removed_ahead.
- Step 3 → Convert back to rank: new_rank = new_people_ahead + 1.
Summary
Summary
- When people ahead leave, reduce the person's rank by the number of those removed.
- Removals behind the person do not change their rank (only the total decreases).
- For mixed removals, count only those who were ahead and subtract them from the old rank.
- To find new rank from bottom, update total first then convert: new_bottom = new_total - new_top + 1.
Example to remember:
If someone is 12th and 3 people ahead leave, new rank = 12 - 3 = 9th.
