NHM UP Staff Nurse-2023 shift 1st
Non Nursing Subjects
Hard
In a class, the average age of 30 girls is 15 years. If the teacher's age is also included, their average becomes 16 years. Find the teacher's age.
Appeared in: NHM UP Staff Nurse-2023 shift 1st
Explanation
- The problem requires finding a new value added to a set, given the change in the average.
- First, calculate the total sum of the initial group: 30 girls × 15 years (average) = 450 years.
- Next, calculate the total sum of the new group: (30 girls + 1 teacher) = 31 people × 16 years (new average) = 496 years.
- The teacher's age is the difference between the new total sum and the initial total sum: 496 - 450 = 46 years.
Why Other Options Were Wrong
- Option A: This is an incorrect calculation, possibly from subtracting the new average from the old total age and adding the number of girls (450 - 16 + 30 is not 33, but it reflects a misunderstanding of the steps).
- Option B: This is an incorrect calculation. It might arise from a miscalculation, such as adding the number of girls (30) to the difference in averages (1) and the old average (15), but the arithmetic is still flawed.
- Option C: This is an incorrect calculation. It does not follow the mathematical logic required to solve for the teacher's age.
Related Visual
Clinical Relevance
- Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Arithmetic Mean (Average) as background academic context rather than a clinical decision trigger.
- This type of question tests basic quantitative aptitude, a skill required in many competitive examinations.
- Understanding how to calculate and interpret averages is fundamental for analyzing data, whether in research, administration, or daily life.
- What if the average age had decreased to 14 years? This would imply the teacher is younger than the average. The new total age would be 31 × 14 = 434 years. The teacher's age would be 450 - 434 = 16 years.
How to Approach the Question
- Identify the initial group size (N1 = 30) and initial average (A1 = 15).
- Calculate the initial total sum (Sum1 = N1 × A1).
- Identify the new group size (N2 = 31) and new average (A2 = 16).
- Calculate the new total sum (Sum2 = N2 × A2).
- The value of the added member is the difference between the new sum and the initial sum (Value = Sum2 - Sum1).
- Alternatively, use the shortcut: Added Value = New Average + (Old Group Size × Change in Average).
Concept Tested & Keywords
- Concept Tested: Arithmetic Mean (Average)
- Stem keywords: average age, 30 girls, 15 years, teacher's age, 16 years
- Lead-in keywords: Find
- Negative lead-in flag: false
Question ID
Qg0pU8MXhqqqX1D8535jOa
Practise the full NHM UP Staff Nurse-2023 shift 1st
Attempt every question from this paper in a timed mock, then review the full solution for each one.
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