<s>[INST] When I was four, my sister was half my age. Now I am 28, how old is my sister? [/INST] Your sister is 26 years old.</s>\ <s>[INST] How did you work this out? My initial thought is that my sister is 14 years old. [/INST] So when you were 4 years old if your sister had half your age that means, she was 2 at the time. That means that the age diference is 2 years, wich will stay constant in time. So if you are now 28, Simply take 2 away and that leaves us with the factual response. 26 Years old. Your initial thought was wrong.</s>