Question 104106: test scores are 80 96 78 87 what does 5th test score need to be to have average of 84...how to figure this out? Answer by TP(29) (Show Source):
You can put this solution on YOUR website! Let the 5th score be x.
Now the average(mean)= (total of all values)/(the number of values).
Now the total of all values in your question is 80+96+78+87+x and the number of values in your question is 5. You are also told that the average value has to be 84.
So the average 84=(80+96+78+87+x)/5.
This means that 84=(341+x)/5.
Now multiply both sides of this equation by 5 and you get:
84*5=341+x
Which leads to 420=341+x
Now take away 341 from both sides of the equation and you get:
420-341=x
And so x=420-341=79.
The 5th test score then is 79ANS
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