SOLUTION: Going into the final exam, which counts as three grades, Mark has test scores of 65, 79, 83, and 68. What score does Mark need on the final exam in order to have an average of 70?

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Question 336931: Going into the final exam, which counts as three grades, Mark has test scores of 65, 79, 83, and 68. What score does Mark need on the final exam in order to have an average of 70?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
To find the average of a set of numbers, you add the numbers and divide by how many numbers you added.
%2865%2B79%2B83%2B68%2Bx%29%2F5+=+70 x = the score Mark needs on his final to get an overall average of 70.
%28295%2Bx%29%2F5+=+70 Multiply both sides by 5.
295%2Bx+=+350 Now subtract 295 from both sides.
x+=+55 This is the score that Mark needs on his final.