Answer: Marna has to answer more than 16 answers to win the game.
Explanation:
Le 'x' be the number of correct answers.
If Marna is getting -5 points each time she guess the correct answer.
Then the total points she get after x correct answers= -5x
If to win the game, Marna must have a score of less than -80 points.
⇒

If we multiply (-1) on both sides the inequality will reverse

Divide both sides by 5, we get

Marna has to answer more than 16 answers to win the game.