SOLUTION: After five Tests, a student has an average mark of 67%. How many marks does this student need in the sixth Test to have an average of 70%?

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Question 959316: After five Tests, a student has an average mark of 67%. How
many marks does this student need in the sixth Test to have an
average of 70%?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
[(67*5)+X]/6=70
(335+X)/6=70
335+X=6*70
335+X=420
X=420-335
X=85 ANS FOR THE 6TH TEST MARK.
PROOF:
(335+85/6=70
420/6=70
70=70