<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
When I was 6 years old my sister was half my age. how old is she now I am 70?<|im_end|>
<|im_start|>assistant
When you were 6 your sister was 3 years younger. If your age is 70 her age would be 67.<|im_end|>
<|im_start|>user
How old was she when I was 2?<|im_end|>
<|im_start|>assistant
When you were 2, she was not born yet.
If you insist on a number, -1 would be the answer. -1 years old meaning, she will be born in 1 year.<|im_end|>