Answer: -24 feet
Step-by-step explanation: ascending is rising so you would subtract feet, which in this case is 8 feet. after that you would consider that since she is underground the feet would be negative because she is below ground level which is zero. once you subtract it then you would get a grand total of -24 feet or 24 feet below the earth's surface but more than likely the answer would be -24 ft.
hope this was helpful :)- hailey <3