SOLUTION: A student has earned scores of 87, 81, and 88 on the first 3 of 4 tests. If the student wants an average (arithmetic mean) of exactly 87, what score must she earn on the fourth tes

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Question 285316: A student has earned scores of 87, 81, and 88 on the first 3 of 4 tests. If the student wants an average (arithmetic mean) of exactly 87, what score must she earn on the fourth test?
A. 85
B. 86
C. 87
D. 92
E. 93
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
(87+81+88+X)/4=87
(256+X)/4=87
256+X=4*87
256+X=348
X=348-256
X=92 IS REQUIRED ON THE 4 th TEST.
ANSWER D) 92.
PROOF:
(87+81+88+92)/4=87
348=4*87
348=348