SOLUTION: A Student has scores of 73,79, and 81 on three government exams. What score does she need on a fourth exam to give her an average of 80 or better?

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Question 148518: A Student has scores of 73,79, and 81 on three government exams. What score does she need on a fourth exam to give her an average of 80 or better?


Found 2 solutions by jim_thompson5910, jojo14344:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Let x=score on fourth exam

So the average A of all 4 exams are
A=%2873%2B79%2B81%2Bx%29%2F4


Since the average must be greater than or equal to 80, this means that the right side is greater than or equal to 80

%2873%2B79%2B81%2Bx%29%2F4%3E=80 Set the right side greater than 80


73%2B79%2B81%2Bx%3E=320 Multiply both sides by 4.


x%2B233%3E=320 Combine like terms on the left side.


x%3E=320-233 Subtract 233 from both sides.


x%3E=87 Combine like terms on the right side.


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Answer:

So the answer is x%3E=87 which means that the student must get an 87 or better on the 4th exam.

Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!
Simple averaging, %28E%5B1%5D%2BE%5B2%5D%2BE%5B3%5D%2BE%5B4%5D%29%2F4=+Average
Add all highlight%28E%29xams then divide by 4 to get Average right?
%2873%2B79%2B81%2BE%5B4%5D%29%2F4=80
E%5B4%5D=%2880%2A4%29-73-79-81
E%5B4%5D=87 -------------> should be the final score AT LEAST to have 80 Ave.
The higher the final score of course(>87) the higher the average.
Thank you,
Jojo