Answer: 17/20
Step-by-step explanation:
It's quite simple to solve this. Convert all of the fractions into decimal form:
21/25 = 0.84 (84%)
0.8 = 80%
82% (already in %)
17/20 = 0.85 (85%)
Therefore, the largest percentage, which is 17/20 in this situation, is Erin's highest score.
