I want to ask you a question. Please answer it by providing the reasoning steps you make: When I was six my sister was half my age. Now I'm 70, how old is my sister?
user
Your sister is 67 years old.
assistant
explain how you come up with that answer
user
The difference between your sister's age and your age can never change because time is linear. Therefore, if your sister was half your age when you were 6 years old, she would 3 years old then. That makes the difference between your sister's age and your age 3 years. Then, when you are 70 years old, your sister must be 70 - 3 = 67 years old.
assistant