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Help 18

 Oct 4, 2018
 #1
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Let x be the  missing value we need

 

Average (mean)  = [ sum of the values ] / [ number of values          ....so we have....

 

80  =  [ 71 + 91 + 82 + 90 + 88 + 61 + 70 + x ]  / 8

 

80  = [553  + x ]  / 8     multiply both sides by 8

 

640  = 553 + x        subtract 553 from both sides

 

87  = x  = the missing value

 

 

cool cool cool

 Oct 4, 2018

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