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

Let’s start by setting up an equation to represent the relationship between your age and your sister’s age when you were six years old:

Let x be your sister’s age when you were six.
Then, your age at that time would be 6 years old.

We know that your sister’s age was half your age at that time, so we can write:

x = (1/2) * 6

Simplifying this expression, we get:

x = 3

So your sister was 3 years old when you were 6.

Now, we need to find your sister’s current age, given that you are now 70 years old. Since you and your sister have aged the same amount of time, we can simply add 64 (the difference between your age now and when you were 6) to your sister’s age when you were 6:

current age of your sister = 3 + 64 = 67

Therefore, your sister is currently 67 years old.