Question 260539: Sarah has gotten scores of 83, 76, and 69 on her first three tests. What score must she get on her fourth test to keep an average of 81 or greater.
fourth test = x
x = (83 + 76 + 69)/3
x = 76
Is this correct?
Answer by drk(1908)   (Show Source):
You can put this solution on YOUR website! These are the first three tests: 83, 76, and 69
we want an average of 81 over 4 tests. Think totals.
81 x 4 = 324.
She needs 324 points for an 81 average
right now we have our three tests adding to 228
by subtracting 324 - 228 we get 96.
So, she needs 96 on the fourth test to get 81 %
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alternate method: compare all scores to 81 and look at over (+) and under (-)
83: +2
76: -5
69: -12
this gives us - 15. SHe needs +15 to get 81, so, add this to 81: 81 + 15 = 96
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