document.write( "Question 941532: Samantha spent a total of $420 for daily expenses during her vacation in Mexico. She noted that if she spent $7 less per day, she could have stayed for another 5 days. The number of days she actually spent on her vacation is: \n" ); document.write( "
Algebra.Com's Answer #573952 by stanbon(75887)\"\" \"About 
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Samantha spent a total of $420 for daily expenses during her vacation in Mexico. She noted that if she spent $7 less per day, she could have stayed for another 5 days. The number of days she actually spent on her vacation is:
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\n" ); document.write( "420 = (# of days)*(cost per day)
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\n" ); document.write( "(cost per day-7)(days + 5) = 420
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\n" ); document.write( "Simplify::
\n" ); document.write( "d*c = 420
\n" ); document.write( "(c-7)(d+5) = 420
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\n" ); document.write( "cd + 5c - 7d - 35 = 420
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\n" ); document.write( "420 + 5c - 7d - 35 = 420
\n" ); document.write( "5c - 7d = 35
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\n" ); document.write( "Substitute for \"c\" and solve for \"d\"::
\n" ); document.write( "c = 420/d =
\n" ); document.write( "5(420/d) - 7d = 35
\n" ); document.write( "2100 - 7d^2 = 35d
\n" ); document.write( "d^2 + 5d - 300 = 0
\n" ); document.write( "Positive solution::
\n" ); document.write( "d = 15 days
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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