<s>[INST] 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? [/INST] Your sister is 67 years old.</s>\ <s>[INST] explain how you come up with that answer [/INST] 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.</s>