Question

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?
A) 86
B) 89
C) 90
D) 92

Answer 1

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 =
`((85*0.1)+(90*0.15)+(80*0.25)+(100*0.5))/(1) \\=(92)/(1)\\=92`

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

ANSWER: D