Answer:
b) 91
Step-by-step explanation:
Step 1: Multiple marks by its weights
Homework average: 95 x 20% = 19
Quiz average: 90 x 20% = 18
Test average: 87 x 40% = 34.8
Final exam: y x 20% = 0.2y
Step 2: Add all weighted averages and find y
19+18+34.8+0.2y = 90
71.8 + 0.2y = 90
y = 18.2/0.2
y = 91
Therefore, Anna needs to score minimum 91 in the final exam so that she can score a 90 in class.
Option b is correct.
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