15 years hence a man will be just 4 times as old as he was 15 years ago. His present age is -?

Appeared in: AIIMS Manglagiri NO - 2019

Explanation

The problem is solved by setting up a linear equation based on the given information.
Let the present age be 'x'. The equation becomes: x + 15 = 4(x - 15).
Solving the equation: x + 15 = 4x - 60, which simplifies to 3x = 75.
Therefore, x = 25. The man's current age is 25 years.

Option A: If the present age is 10, then 15 years ago his age would be -5, which is not possible. Also, his age in 15 years would be 25. 25 is not 4 times -5.
Option B: If the present age is 15, his age 15 years ago was 0. His age in 15 years will be 30. 30 is not equal to 4 times 0.
Option C: If the present age is 20, his age in 15 years will be 35, and his age 15 years ago was 5. 35 is not 4 times 5 (which is 20).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Solving linear equations from word problems, specifically age-related problems as background academic context rather than a clinical decision trigger.
This question is not related to a clinical or nursing scenario.
It tests basic mathematical and logical reasoning skills, which are a component of the aptitude section in many nursing entrance and recruitment examinations.
These skills are foundational for tasks like medication dosage calculation, interpreting charts, and managing time-sensitive protocols, although this specific problem is purely abstract.

How to Approach the Question

First, carefully read the problem to identify the unknown quantity and the relationships described. The unknown here is the 'present age'.
Assign a variable to the unknown quantity. Let 'x' be the man's present age.
Translate the phrases in the word problem into algebraic expressions. '15 years hence' becomes 'x + 15', and '15 years ago' becomes 'x - 15'.
Formulate an equation that represents the relationship given in the problem: 'will be just 4 times as old as' translates to an equality: x + 15 = 4 * (x - 15).
Solve the resulting linear equation for the variable 'x'.
Check your answer by plugging the value of 'x' back into the original problem statement to ensure it holds true.

Concept Tested & Keywords

Concept Tested: Solving linear equations from word problems, specifically age-related problems.
Stem keywords: age, 15 years hence, 15 years ago, 4 times as old
Lead-in keywords: present age

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