SOLUTION: Going into the final exam, which will count 2/3's of the final grade, Mike has test scores of 86, 80, 84, 90. What score does Mike need on the final in order to earn a B, which re

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Going into the final exam, which will count 2/3's of the final grade, Mike has test scores of 86, 80, 84, 90. What score does Mike need on the final in order to earn a B, which re      Log On


   

Question 268616: Going into the final exam, which will count 2/3's of the final grade, Mike has test scores of 86, 80, 84, 90. What score does Mike need on the final in order to earn a B, which requires an average score of 80? What score would he need for an A?
Do I simply find the average of the test scores and assume it's 1/3 of his final grade?
Does it look like this:
(85)1/3+ x2/3= 80
and to find his grade for an "A":
85(1/3)+ x2/3+90
Thank you!
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Going into the final exam, which will count 2/3's of the final grade,
Mike has test scores of 86, 80, 84, 90.
What score does Mike need on the final in order to earn a B, which requires an average score of 80?:
:
I think you can do it that way, this is the way I would do it:
Average the 4 grades that represent 1/3
%2886%2B80%2B84%2B90%29%2F4 = 85
:
x = 2/3 the final grade or twice as much as first 4 grades
:
%2885+%2B+2x%29%2F3 = 80
multiply by 3
85 + 2x = 3(80)
2x = 240 - 85
2x = 155
x = 155%2F2
x = 77.5 to get 80% for a B
:
Your way would get the same answer.
:
What score would he need for an A?