Question 285789: Your grades in your math class on the last five tests are 83, 92, 78, 96, and 89 and you wish to have an overall average of 90 in the class. What grade must you average on your next three tests?
A. 89 B. 90 C. 92 • D. 94 E. None of these.
Answer by Grinnell(63)   (Show Source):
You can put this solution on YOUR website! OK you are dealing with averages the sum of a group of numbers divided by the AMOUNT of different numbers is an average or a 'mean'. So what do we have here?
Five test scores PLUS identical scores on three more tests DIVIDED by the total of 8 tests in all equals an average of 90. Do the Math...
438 plus 3x= 720
3x=282
x=94
so the scores would look like this: 83, 92, 78, 96, 89, 94, 94, 94 When you divide their sum by 8 you get the average score of 90.
The answer to problem is D.
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