document.write( "Question 510403: a students needs to average 80 on her tests in order to earn a B in her math class. Her average afterr 4 tests is 77.5 What score is needed on the fifth test in order to raise the average to 80?
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Algebra.Com's Answer #341808 by Maths68(1474)\"\" \"About 
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Total of 4 tests
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\n" ); document.write( "Average = 77.5
\n" ); document.write( "Total = x
\n" ); document.write( "Number of tests = 4\r
\n" ); document.write( "\n" ); document.write( "Total/Number of test = Average
\n" ); document.write( "x/4=77.5
\n" ); document.write( "x=77.5*4
\n" ); document.write( "x=310\r
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\n" ); document.write( "\n" ); document.write( "Average of 5 test
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\n" ); document.write( "Socre in fifth test = y
\n" ); document.write( "Average needed = 80
\n" ); document.write( "Total = x+y (score in all 4 tests + score in 5th test)
\n" ); document.write( "Number of tests = 5\r
\n" ); document.write( "\n" ); document.write( "Total / Number of test = Average needed
\n" ); document.write( "(x+y)/5=80
\n" ); document.write( "(310+y)/5=80
\n" ); document.write( "310+y=80*5
\n" ); document.write( "310+y=400
\n" ); document.write( "y=400-310
\n" ); document.write( "y=90\r
\n" ); document.write( "\n" ); document.write( "Student has to score 90 in 5th test in order to raise the average to 80.
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