Answer:
62.5% of the class
Step-by-step explanation:
If 12 students is 3/8 of the class, the ones who earned A's, then 5/8 did not earn A's.
Let c represent the total number of students in the class.
Then (3/8)c = 12, and c = (8/3)(12) = 32.
5/8 of these 32 students did not earn A's: (5/8)(32) = 20.
These 20 students constitute 20/32 of the class, or 0.625 of the class, or 62.5% of the class.