Introduction
This pattern deals with finding the total number of people or objects when the position of one person from both ends (left and right) is given. It’s one of the most common and simple ranking problems in reasoning tests.
Understanding this concept helps you easily determine the total count in a line or row when two positional references are known.
Pattern: Position from Both Ends
Pattern
The key idea: Total = Left position + Right position - 1.
This formula removes the double counting of the same person, as one person is counted once from each side.
Step-by-Step Example
Question
In a line, Ramesh is 6th from the left and 8th from the right. Find the total number of people in the line.
Solution
-
Step 1: Identify the given positions
Left position = 6, Right position = 8. -
Step 2: Apply the formula
Total = Left + Right - 1 = 6 + 8 - 1 = 13. -
Final Answer:
13 people in total -
Quick Check:
If Ramesh is 6th from left, there are 5 people before him and 7 after him → 5 + 1 + 7 = 13 ✅
Quick Variations
1. Sometimes, one position is from the top and another from the bottom (e.g., class ranks).
2. Can also appear in objects (like books in a shelf or houses in a street).
3. The formula works for both vertical (top-bottom) and horizontal (left-right) arrangements.
Trick to Always Use
- Step 1: Add both given positions.
- Step 2: Subtract 1 to remove double counting of the same person.
- Step 3: The result gives the total number of people or objects.
Summary
Summary
- Total = Left position + Right position - 1.
- Used when a single person’s position from both ends is given.
- Applies to ranks, rows, or any linear arrangement.
- Always subtract 1 to avoid counting the same person twice.
Example to remember:
If someone is 4th from left and 7th from right → Total = 4 + 7 - 1 = 10 ✅
Hint: Add both ranks and subtract 1.
Common Mistakes: Forgetting to subtract 1 after adding both positions.