Question 7
My mother is three times older than my sister. My father is 30 years older than me. I was 5 years old when my sister was born. If the present age of my sister is 15 years, then the difference between my mother’s and father’s age is ____.
Editorial interpretation: “three times older” is read as “three times as old”, as intended by the key.
Editorial interpretation: “three times older” is read as “three times as old”, as intended by the key.