SOLUTION: shawn needs to have a 90% average for his exam grade to make an A for the quarter there are three tests in the quarter and his first two exams percentage were 91%,87% what score mu

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Question 1822: shawn needs to have a 90% average for his exam grade to make an A for the quarter there are three tests in the quarter and his first two exams percentage were 91%,87% what score must he get on the third exam to obtain a 90% average?
90 x 3 = 270
270-87 - 91 = 92
Found 2 solutions by longjonsilver, ahmad.rakhaa:
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
let his third exam result be x, so that we need the average of all 3 to be equal to 90%. This is the English version, now for the maths version ...
%2891%2B87%2Bx%29%2F3+=+90
%2891%2B87%2Bx%29+=+270
therefore x+=+270+-+91+-+87
x = 92%
cheers
Jon.

Answer by ahmad.rakhaa(1) About Me  (Show Source):
You can put this solution on YOUR website!
90 x 3 = 270
270-87 - 91 = 92