The Correct Answer and Explanation is:
The correct answer is 23.
To solve this problem, we must first establish the current ages of both Brian and his brother. The information given states that Brian is currently 8 years old. His brother is twice his age, which means we need to multiply Brian’s age by two to find the brother’s current age. The calculation is 8 multiplied by 2, which equals 16. Therefore, at this moment, Brian is 8 and his brother is 16.
The most critical piece of information we can determine from their current ages is the age difference between them. This gap in age will remain constant throughout their lives. To find it, we subtract Brian’s age from his brother’s age: 16 minus 8 equals 8. This tells us that the brother is, and always will be, exactly 8 years older than Brian.
Now we can determine the brother’s age in the future scenario presented in the question. The question asks for the brother’s age when Brian turns 15. Since we have established that the brother is always 8 years older than Brian, we can simply add that constant age difference to Brian’s future age. When Brian is 15 years old, his brother’s age will be 15 plus the 8 year difference. This calculation, 15 + 8, results in 23.
An alternative method confirms this result. We can calculate how many years pass between Brian’s current age and his future age: 15 minus 8 is 7 years. In 7 years, Brian will be 15. We must then add these same 7 years to his brother’s current age. The brother, who is currently 16, will be 16 plus 7, which also equals 23. Both methods logically lead to the same conclusion. It is important to note that this correct answer of 23 is not listed among the multiple choice options provided in the image.
