Age Calculation: When You Were 4, Your Sister Was Half Your Age

Introduction

This is a common puzzle that often circulates on the internet or social media. The puzzle goes as follows: when you were 4, your sister was half your age. Now that you are 100, how old is your sister now? The quick and generally accepted answer is that your sister is 98 years old. However, exploring this puzzle in detail can provide interesting insights into how age calculations work.

Understanding the Math

The first step is to understand the age difference between you and your sister. When you were 4, your sister was 2, half your age (4/2 2). This establishes a consistent age gap of 2 years. Since this age difference remains constant throughout your lives, you can calculate your sister's current age by subtracting 2 years from your own age:

Mathematical Calculation

1. Your age now: 100 2. Age difference: 2 3. Sister's age: 100 - 2 98

Therefore, if you are 100 years old, your sister is 98 years old. This calculation is straightforward and relies on the assumption that the age difference remains constant over time.

Potential Pitfalls

However, it is worth considering some potential pitfalls. For instance, if you claim to be 100 years old, your memory might be faulty. Or, if you are alive, your sister might not be. These considerations demonstrate the importance of realistic assumptions when solving such puzzles.

Real-World Applications

Understanding age calculations can be useful in various real-world scenarios. For example, when dealing with time-based calculations in mathematics, finance, or even in everyday life, knowing the basic principles of age differences can help avoid errors.

Conclusion

When you were 4, and your sister was half your age (2 years old), the age difference of 2 years remained constant. Therefore, when you are 100, your sister would be 98 years old. This understanding not only helps solve puzzles but also provides a solid foundation for solving age-related mathematical problems in everyday life.