document.write( "Question 825653: On the first 3 exams of his geometry class, Luis got an average score of 81.\r
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Algebra.Com's Answer #497499 by math-vortex(648)\"\" \"About 
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document.write( "Hi, there--\r\n" );
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document.write( "THE PROBLEM:\r\n" );
document.write( "On the first 3 exams of his geometry class, Luis got an average score of 81. \r\n" );
document.write( "What does he need on the next exam to have an overall average of 83?\r\n" );
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document.write( "A SOLUTION:\r\n" );
document.write( "Let x be the score Luis needs on his next exam.\r\n" );
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document.write( "The formula for finding the average score is \r\n" );
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document.write( "[the sum of the scores] / [the number of scores] = [average score]\r\n" );
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document.write( "Luis had an average of 81 after 3 exams, so we could work backwards from the average \r\n" );
document.write( "score to find the sum of his first three scores. We multiply 81*3=243.\r\n" );
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document.write( "The sum of his first three scores is 243. To find his average score after 4 exams, Luis\r\n" );
document.write( "will add his 4th exam score to 243 and divide the sum by 4. Luis wants an overall score of 83.\r\n" );
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document.write( "Let's write an equation for that.\r\n" );
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document.write( "243 + x is the sum of the first three score plus the score needs on his 4th exam.\r\n" );
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document.write( "We divide by 4 because we are taking the average of 4 scores.\r\n" );
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document.write( "Luis needs his average to equal 83.\r\n" );
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document.write( "(243+x)/4 = 83\r\n" );
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document.write( "Solve for x. Multiply both sides by 4.\r\n" );
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document.write( "243 + x = 83 * 4\r\n" );
document.write( "243 + x = 332\r\n" );
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document.write( "Subtract 243 from each side.\r\n" );
document.write( "x = 332 - 243\r\n" );
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document.write( "Simplify.\r\n" );
document.write( "x = 89\r\n" );
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document.write( "Luis needs a score of 89 on his 4th exam.\r\n" );
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document.write( "Hope this helps!\r\n" );
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document.write( "Mrs. Figgy\r\n" );
document.write( "math.in.the.vortex@gmail.com\r\n" );
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