document.write( "Question 1153460: A computer manufacturer has a supply of 3600 computers. It wishes to ship 128 computers each week until its supply drops to 2000 computers. How long will this take?
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Algebra.Com's Answer #775677 by Theo(13342)\"\" \"About 
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the difference between 3600 and 2000 = 1600.
\n" ); document.write( "divide that by 128 to get 12.5
\n" ); document.write( "if would take 12.5 weeks for the inventory to reduce from 3600 to 2000.
\n" ); document.write( "multiply 128 by 12.5 and you get 1600.
\n" ); document.write( "that's the reduction required to get from 3600 to 2000.
\n" ); document.write( "you can use the arithmetic progression formula to get the same answer.
\n" ); document.write( "that formula is An = A1 + (n-1) * d
\n" ); document.write( "An = 2000
\n" ); document.write( "A1 = 3600
\n" ); document.write( "d = -128 because you are subtracting 128 each time rather than adding.
\n" ); document.write( "formula becomes:
\n" ); document.write( "2000 = 3600 + (n-1) * -128
\n" ); document.write( "subtract 3600 from both sides of the equation to get:
\n" ); document.write( "2000 - 3600 = (n-1) * -128
\n" ); document.write( "simplify to get:
\n" ); document.write( "-1600 = (n-1) * -128
\n" ); document.write( "divide both sides by -128 to get
\n" ); document.write( "-1600 / -128 = (n-1)
\n" ); document.write( "solve for (n-1) to get 12.5
\n" ); document.write( "the formula becomes:
\n" ); document.write( "2000 = 3600 * 12.5 * -128
\n" ); document.write( "evaluate to get:
\n" ); document.write( "2000 = 2000
\n" ); document.write( "this confirms the solution is correct
\n" ); document.write( "either way you get the same answer, although use of the arithmetic progression formula might be a little trickier.
\n" ); document.write( "the basic solution i used was find the difference and divide it by 128 to get the number of weeks.
\n" ); document.write( "3600 - 2000 = 1600
\n" ); document.write( "1600 / 128 = 12.5
\n" ); document.write( "if you graph the equation of y = 3600 - 128 * x, it would look like this:\r
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\n" ); document.write( "\n" ); document.write( "x represents the number of weeks.
\n" ); document.write( "y represents the the inventory after the number of weeks.
\n" ); document.write( "when x = 0, you have 3600.
\n" ); document.write( "when x = 12.5, you have 2000.
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