In a line of girls, Rani is 10^th from the left and 12^th from the right. How many girls are in the line?

Appeared in: NHM MP Staff Nurse - 2015

Explanation

The problem requires finding the total number of people in a row when one person's rank is given from both the left and right ends.
The standard formula for this is: Total = (Rank from Left + Rank from Right) - 1.
Applying the formula with the given values: Total = (10 + 12) - 1.
This simplifies to 22 - 1, which equals 21.
The subtraction of 1 is necessary because the person (Rani) is counted once from the left and once again from the right, leading to a double count.

Option A: This value is incorrect. It may result from a miscalculation, such as (10 + 12) - 2, which has no logical basis for this type of problem.
Option C: This is the result of simply adding the two positions (10 + 12 = 22) without correcting for the double count. This error occurs when one forgets that the person is included in both the count from the left and the count from the right.
Option D: This value is incorrect. It might be the result of an erroneous calculation like (10 + 12) + 1, which incorrectly adds an extra person instead of removing the double count.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Logical Reasoning - Order and Ranking as background academic context rather than a clinical decision trigger.
While this is a non-clinical question, the logical reasoning skills tested are essential for nurses.
Nurses use systematic problem-solving daily, from calculating medication dosages to prioritizing patient care, which requires clear, logical thinking.
This type of problem-solving helps in developing attention to detail, a critical trait for preventing errors in a clinical setting.

How to Approach the Question

First, carefully read the question to identify the key information: a single person's position is given from both the left and right ends of a line.
Recognize this as a classic order and ranking problem.
Recall the specific formula for this scenario: Total number of people = (Position from Left + Position from Right) - 1.
Understand the logic behind the formula: you must subtract 1 to avoid counting the same person twice.
Substitute the given numbers into the formula: Total = (10 + 12) - 1.
Perform the calculation: 22 - 1 = 21. Select the corresponding option.

Concept Tested & Keywords

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Practise the full NHM MP Staff Nurse - 2015

Attempt every question from this paper in a timed mock, then review the full solution for each one.