Answer:
He obtained 11.2 points
Step-by-step explanation:
He obtained 20 balls and was penalized 3 points.
If each red ball is 0.5 points off, then 3/0.5=6
6 of his obtained balls were red balls, penalizing 3 points.
So, 20-6=14
The rest of his 14 balls were green balls, each worth 0.8
So, 14 × 0.8 = 11.2
So he obtained a total of 11.2 points
