Age Difference Calculation: How Old is Your Sister?

Commonly posed questions about the age of siblings can sometimes confuse or test one's basic arithmetic reasoning skills. Consider this question: When you were 10, your sister was 5. Now you are 40. How old is your sister now?

Simple Arithmetic Logic

The key to solving such a problem is understanding the consistent age difference. If you were 10 and your sister was 5, the difference in your ages was 5 years. This difference remains constant over time. Therefore, when you are 40 now, your sister will be 5 years younger, which is 40 - 5 35.

Persistent Age Difference

A visual explanation may help solidify the concept. If we use a timeline:

When you were 10 (Year A), your sister was 5 (Year B). When you are 40 (Year C), your sister would be 40 - 5 35 (Year D).

Alternatives and Misunderstandings

Sometimes, there can be twists in the question. For example:

When you were 4, your sister was twice your age. If you were 4, her age was 4 * 2 8. Now, you are 40, and the age difference remains 4. So, your sister would be 40 - 4 36, and her age is 8 28 36.

This alternative scenario is incorrect based on the consistent age difference. The key is to stick to the initial difference of 5 years.

Conclusion

Age calculations based on consistent differences are straightforward when approached with the right logic. The correct answer to the original question is that your sister is 35 years old, as she has aged consistently by the 5-year gap that existed when you were 10.

Key Takeaways:

The age difference between siblings remains constant over time. Use basic arithmetic to solve age-related problems.

Note: If you encounter questions or problems on platforms like Quora that are poorly written or misleading, it’s advisable to flag them for review and clarity.