document.write( "Question 702422: If my exam grades are 79, 93, 91, and 68, what grade would I need on my next exam to have an average of 80? I need to learn how to work this problem. \n" ); document.write( "

Algebra.Com's Answer #432978 by jim_thompson5910(35256) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let x = next exam grade\r
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\n" ); document.write( "\n" ); document.write( "Add up the grades, divide by 5 to average them, then set that equal to the desired average grade of 80\r
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\n" ); document.write( "\n" ); document.write( "(79+93+91+68+x)/5 = 80\r
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\n" ); document.write( "\n" ); document.write( "Now solve for x\r
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\n" ); document.write( "\n" ); document.write( "(79+93+91+68+x)/5 = 80\r
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\n" ); document.write( "\n" ); document.write( "79+93+91+68+x = 80*5\r
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\n" ); document.write( "\n" ); document.write( "79+93+91+68+x = 400\r
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\n" ); document.write( "\n" ); document.write( "331+x = 400\r
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\n" ); document.write( "\n" ); document.write( "x = 400 - 331\r
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\n" ); document.write( "\n" ); document.write( "x = 69\r
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\n" ); document.write( "\n" ); document.write( "So you need a 69 on the next exam to get an average of 80. If you score higher than 69, then your average will be larger than 80. \n" ); document.write( "

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