document.write( "Question 1116968: A bookstore can purchase several calculators for a total cost of $160. If each calculator cost $4 less, the bookstore could purchase 2 additional calculators at the same total cost. How many calculators can be purchased at the regular price? \n" ); document.write( "

Algebra.Com's Answer #731895 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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A bookstore can purchase several calculators for a total cost of $160.
\n" ); document.write( " If each calculator cost $4 less, the bookstore could purchase 2 additional calculators at the same total cost.
\n" ); document.write( " How many calculators can be purchased at the regular price?
\n" ); document.write( ":
\n" ); document.write( "let c = no. of calc purchased at regular price
\n" ); document.write( "then
\n" ); document.write( " $\"160%2Fc\"$ = original price per calc
\n" ); document.write( ":
\n" ); document.write( " $\"160%2Fc\"$ - 4 = $\"160%2F%28%28c%2B2%29%29\"$
\n" ); document.write( "multiply by c(c+2), cancel denominators
\n" ); document.write( "160(c+2) - 4c(c+2) = 160c
\n" ); document.write( "160c + 320 - 4c^2 - 8c = 160c
\n" ); document.write( "subtract 160c to both sides
\n" ); document.write( "320 - 4c^2 - 8c = 0
\n" ); document.write( "0 = 4c^2 + 8c - 320
\n" ); document.write( "simplify, divide by 4
\n" ); document.write( "c^2 + 2c - 80 = 0
\n" ); document.write( "factors to
\n" ); document.write( "(c+10)(c-8) = 0
\n" ); document.write( "positive solution
\n" ); document.write( "c = 8 calculators at regular price \n" ); document.write( "

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