1350 boys and 900 girls are examined in a test. 42% of the boys and 36% of the girls pass the test. The percentage of the total who failed is?

Appeared in: RRB Nsg. Superintendent-20 July 2019 (Shift-2)

Explanation

The core task is to find the total percentage of students who failed, which requires a weighted average calculation.
First, calculate the number of failures for each group (boys and girls) by finding the complement of their pass percentage (100% - pass %).
Number of boys who failed is 58% of 1350, which equals 783.
Number of girls who failed is 64% of 900, which equals 576.
The total number of failed students is the sum of failed boys and girls (783 + 576 = 1359).
The final percentage is this total number of failures (1359) divided by the total number of students (1350 + 900 = 2250), which results in 60.4%.

Option A: This value is incorrect and likely results from a miscalculation, such as incorrectly determining the number of failed students or using the wrong total number of students in the final percentage calculation.
Option B: This is an incorrect calculation. It may arise from errors in calculating the individual failure counts for boys or girls, or an arithmetic error in the final division.
Option C: This value is incorrect. A common mistake that could lead to a close but wrong answer is incorrectly averaging the two failure percentages (58% and 64%) without considering the different group sizes (weighting).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain This question tests the ability to calculate weighted percentages from different subgroups to find an overall percentage as background academic context rather than a clinical decision trigger.
While not a clinical question, the underlying skill of calculating weighted averages is crucial in nursing.
Nurses use this skill for interpreting research data, understanding health statistics in a population (epidemiology), and in administrative tasks like resource allocation based on patient demographics.
For example, calculating the overall infection rate in a hospital requires weighting the rates from different units (like ICU, general ward) by the number of patients in each unit.

How to Approach the Question

First, identify all the given numbers: number of boys (1350), number of girls (900), pass percentage for boys (42%), and pass percentage for girls (36%).
Recognize that the question asks for the percentage of students who FAILED. This means you'll need to convert the 'pass' percentages into 'fail' percentages.
Calculate the number of failed students for each group separately. Do not average the percentages directly.
Sum the number of failed students from both groups to get a total number of failures.
Sum the number of students from both groups to get the total number of students.
Finally, divide the total number of failures by the total number of students and multiply by 100 to find the overall failure percentage.

Concept Tested & Keywords

Concept Tested: This question tests the ability to calculate weighted percentages from different subgroups to find an overall percentage.
Stem keywords: boys, girls, examined, test, pass, failed, percentage
Lead-in keywords: percentage of the total who failed

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Practise the full RRB Nsg. Superintendent-20 July 2019 (Shift-2)

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