SOLUTION: gine earns score of 65,78,85 and 82 on four tests. what grade must she earn on the next test to have an average of 80 ?

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Question 266578: gine earns score of 65,78,85 and 82 on four tests. what grade must she earn on the next test to have an average of 80 ?
Answer by mawskittykat(9) About Me  (Show Source):
You can put this solution on YOUR website!
First of all you need to add all 4 grades
65+78+85+82=310 (you Have)
If you took 5 tests your total would need to be 400 to receive and 80 average overall. Because 400 divided by 5 equals 80
Now you would subtract the 400 you need minus 310 you have.
400-310 = 90.
You would need to score 90 on your next test