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Ms. Donahue uses 4 essays as the basis for her grading. Each essay counts as a percent of the final average.


Essay 1 10%

Essay 2 15%

Essay 3 25%

Essay 4 50%


Joel had the following scores for his work: Essay 1, 85; Essay 2, 90; Essay 3, 80; and, Essay 4, 100.

What is Joel's expected final average?

A86
B89
C90
D92


Verified Answer :

This is NOT the case of adding up the sums of scores and dividing by 4.

This is a weighted average where we take each score and multiply by its weight (% worth) and then do the sum. We finally divide by sum of percentage (10%+15%+25%+50%=100%=1).

So, weighted average = \(\frac{(85*0.1)+(90*0.15)+(80*0.25)+(100*0.5)}{1} \\=\frac{92}{1}\\=92\)

Joel's expected final average is D (92).


ANSWER: D