document.write( "Question 906359: Tom's average grade is 90. If he received the following grades in all his other subjects, what was his math grade? English: 84; History: 91; Science: 89; Spanish: 95 \n" ); document.write( "
Algebra.Com's Answer #549750 by AlgebraLady88(44)\"\" \"About 
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Here, we are primarily interested in finding averages.
\n" ); document.write( "We are told that Tom's average grade is 90 and then the subjects with his grades are listed. Here is how we find his Math grade:\r
\n" ); document.write( "\n" ); document.write( "(English + History + Science + Spanish + Math) / 5 = 90
\n" ); document.write( "(84+ 91+ 89 + 95 + Math) /5 = 90
\n" ); document.write( "(359 + Math)/5 = 90
\n" ); document.write( "Cross multiplying gives us 359 + Math = 90*5
\n" ); document.write( " 359 + Math = 450
\n" ); document.write( " Math = 450 - 359
\n" ); document.write( " Math = 91
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