SOLUTION: Algebra 2 test problem : a student scores on 5 test are 93%, 89%, 72%, 80% and 96% what must the student score on the 6th test so that the average is 88% . I need the formula, I

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Question 333862: Algebra 2 test problem : a student scores on 5 test are 93%, 89%, 72%, 80% and 96% what must the student score on the 6th test so that the average is 88% .
I need the formula, I have the answer..
Thank u....;)
Found 2 solutions by stanbon, jim_thompson5910:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
a student scores on 5 test are 93%, 89%, 72%, 80% and 96% what must the student score on the 6th test so that the average is 88% .
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Let the 6th test score be x$
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Equation:
(93+89+72+80+96+x)/6 = 88
430+x = 528
x = 98%
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Cheers,
Stan H.
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Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Convert each percentage to decimal form to get 0.93, 0.89, 0.72, 0.80, and 0.96


Now let x = score on 6th test


So to find the average of the 6 tests, simply add them up and divide by 6 like so:

%280.93%2B0.89%2B0.72%2B0.80%2B0.96%2Bx%29%2F6


Now set that equal to the given average of 0.88 (88% in decimal form) to get


%280.93%2B0.89%2B0.72%2B0.80%2B0.96%2Bx%29%2F6=0.88


%280.93%2B0.89%2B0.72%2B0.80%2B0.96%2Bx%29%2F6=0.88 Start with the given equation.


0.93%2B0.89%2B0.72%2B0.80%2B0.96%2Bx=0.88%2A6 Multiply both sides by 6.


0.93%2B0.89%2B0.72%2B0.80%2B0.96%2Bx=5.28 Multiply 0.88 and 6 to get 5.28


4.3%2Bx=5.28 Combine like terms.


x=5.28-4.3 Subtract 4.3 from both sides.


x=0.98 Combine like terms.


So the score on the 6th test must be a 98% (multiply 0.98 by 100 to convert it to a percentage) to get an average score of 88%