SOLUTION: Shelby made a list of her test scores: 88,100,92,80,85,94,90. What is the lowest score she can get on her next test to have a mean score of 90?

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Question 654044: Shelby made a list of her test scores: 88,100,92,80,85,94,90. What is the lowest score she can get on her next test to have a mean score of 90?
Found 2 solutions by solver91311, jim_thompson5910:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


If the average is to be 90, then the total score for all of the tests (incuding the one not yet taken) has to be 90 times the number of tests which is one more than the number of tests already taken. Once you have that total, subtract the total of all of the scores already achieved. The result of that calculation is your answer.

John

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Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
(88+100+92+80+85+94+90+x)/8 = 90

(629+x)/8 = 90

629+x = 90*8

629+x = 720

x = 720-629

x = 91

So the lowest score she can get is 91