When I was six, my sister was half my age. Now I’m 70, how old is she?

When you were six years old, your sister was three years old, since half of six is three. This means there is a three-year age difference between you and your sister.

Now that you are 70, you simply subtract that same three-year age difference from your age to find out your sister’s age. So, 70 – 3 = 67.

Therefore, your sister is 67 years old now.