Finding original position from left in an odd-length row: There are 25 boys in a horizontal row. Rahul is shifted 3 places to his right and then occupies the middle position of the row. What was Rahul's original position from the left end?
Verbal Reasoning
Ranking Test
Difficulty: Easy
Choose an option
-
A15th
-
B16th
-
C12th
-
D10th
-
E13th
Answer
Correct Answer: 10th
Explanation
Introduction / Context:Middle-position questions rely on recognizing that in a row of 25, the middle is the 13th position from either end. Shifts then let you back-calculate the original rank.
Given Data / Assumptions:
- Total boys = 25.
- After moving 3 places to the right, Rahul sits at the middle position.
Concept / Approach:Middle index for odd N is (N + 1) / 2 = 13. If final = original + 3 (to the right), then original = final - 3.
Step-by-Step Solution:
Step 1: Middle of 25 ⇒ 13th.Step 2: Original position = 13 - 3 = 10.Verification / Alternative check:Simulate: If Rahul starts at 10th from the left, moving three right lands him at 13th. Correct.
Why Other Options Are Wrong:
- 12th/15th/16th/13th: Do not produce 13th after a +3 shift.
Common Pitfalls:Thinking the center of 25 is 12th or 12.5th; always use (N+1)/2 for odd N.
Final Answer:10th