Riddles about age and time are classic brain teasers because they sound tricky but rely on simple math and careful reading. They usually play with phrases like “half my age” or “years ago,” which can easily confuse anyone who rushes through the question.
This particular riddle “When I was 6, my sister was half my age” is popular because it feels like the answer should change as you both grow older, but the age difference actually stays the same throughout life. Once that clicks, the whole thing suddenly becomes obvious and even a bit funny in hindsight.
Question
When I was 6, my sister was half my age.
Now I’m 70 years old.
How old is my sister?
Answer
Your sister is 67 years old.
Answer Explanation
When you were 6 and your sister was half your age, she was 3 years old, which means there is a fixed 3‑year age difference between you and your sister.
That gap never changes as you both grow older. So, if you are now 70, you simply subtract the 3‑year difference: 70 − 3 = 67.
Many people get tricked because they focus on “half my age” now instead of realizing it only applied at age 6 and was just a way of telling you the age gap.
