<PRE><B>Question 660349</B>
Average = total scores/number of test
x = % on 4th test

(87 + 92 + 84 + x)/4 = 90
(263 + x)/4 = 90
(263+x)/4 (4) = 90(4)
263 + x = 360
x = 360 - 263
x=97% on the fourth test to pass the course

Regarding how you started: 
Out of 500 possible points, 90% is .9(500) or 450 points.
Using 87 + 92 + 84 to determine current points earned as 263
450 - 263 = 187 needed to earn 90% of 500
Scoring 187 points on a 200 point test is 93.5 percent.  However, this solution does not incorporate using an average.

If 93.5 is earned on the fourth test,
87+92+84+94 = 357/4 = 89.25, one would not pass the course.



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