Final answer:
The last two scores could be 10 and -10. When the player scored 40 and -20, their total score increased from 0 to 20. If they score 10 and -10 again, their total score would remain unchanged at 20 because the positive and negative scores cancel each other out.
Step-by-step explanation:
The last two scores could be 10 and -10. When the player scored 40 and -20, their total score increased from 0 to 20. If they score 10 and -10 again, their total score would remain unchanged at 20 because the positive and negative scores cancel each other out.