a boy is 17 years old and his sister is as twice as old. when the boy is 23 what will be the age of his sister

Answer 1

When he was 17 her sister was 34 so when he is 23 which is 6 years later her sister would be 34+6 which is 40 years old

Answer 2

17 * 2 = 34 >> present age of sister

23 - 17 = 6 >> years from now

6 + 34 = ?