SOLUTION: A student earned scores of 83, 78, and 77 on three of four test. What must the student score on the fourth test to have an average(arithmetic mean) of exactly 80?

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Question 292486: A student earned scores of 83, 78, and 77 on three of four test. What must the student score on the fourth test to have an average(arithmetic mean) of exactly 80?
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
A student earned scores of 83, 78, and 77 on three of four test. What must the student score on the fourth test to have an average(arithmetic mean) of exactly 80?
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Let x = score on fourth test
then
(83+78+77+x)/4 = 80
(238+x)/4 = 80
238+x = 320
x = 320-238
x = 82