document.write( "Question 47400: Suppose Amanda's quiz average is 86, and these are her grades: 84,88,82,90,92,x, where x is unknown. Can you determine the missing grade? If yes, calculate. If not, why not? \n" ); document.write( "

Algebra.Com's Answer #31308 by Earlsdon(6294) $\"\"$ $\"About$

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To find the average of a set of numbers (grades), add the numbers and divide by the number of numbers (6 in this case). Amanda's average is 86, so:
\n" ); document.write( " $\"84%2B88%2B82%2B90%2B92%2Bx%29%2F6+=+86\"$ simplify and solve for x.
\n" ); document.write( " $\"436%2Bx%29%2F6+=+86\"$ Multiply both sides of the equation by 6.
\n" ); document.write( " $\"436%2Bx+=+516\"$ Subtract 436 from both sides.
\n" ); document.write( " $\"x+=+80\"$ \r
\n" ); document.write( "\n" ); document.write( "The missing grade is 80.
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