Answer:
The overall score is 75.6
Letter grade is C
Step-by-step explanation:
The question has missing details (See comment section for complete question).
From the complete question, we have:
Proportion:
[tex]Midterm = 15\%[/tex]
[tex]Project = 25\%[/tex]
[tex]Assignment = 40\%[/tex]
[tex]Exam = 20\%[/tex]
Scores
[tex]Midterm = 66[/tex]
[tex]Project = 90[/tex]
[tex]Assignment = 75[/tex]
[tex]Exam = 66[/tex]
Solving (a): The overall score
To do this, we simply calculate the mean of the given data.
The mean is calculated by multiplying each proportion by the scores..
So, we have:
[tex]Overall = 15\% * 66 + 25\% * 90 + 40\% * 75 + 20\% * 66[/tex]
[tex]Overall = 9.9 + 22.5 + 30 + 13.2[/tex]
[tex]Overall = 75.6[/tex]
Solving (b): The letter grade
From the question, we have:
[tex]A: Mean \ge 90[/tex]
[tex]B: 80 \le Mean < 90[/tex]
[tex]C: 70 \le Mean < 80[/tex]
The overall score falls in the following category:
[tex]C: 70 \le Mean < 80[/tex]
Because:
[tex]70 \le 75.6 < 80[/tex]
Hence, the letter grade is C