document.write( "Question 370575: Liz commutes 30 mi. to her job each day. She Finds that if she drives 10 mi/h faster it takes her 6 minutes less to get to work. Find her new speed.\r
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Algebra.Com's Answer #264131 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!


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document.write( "Let r represent her old speed
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document.write( "d = r*t  
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document.write( "30 = r*t
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document.write( "30/r = t
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document.write( "Multiplying thru by 10r(r+10) so as all denominators = 1
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document.write( "300r = 300(r+10) - r(r+10)
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document.write( "300r = 300r + 3000 - r^ - 10r
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document.write( "r^2 + 10r - 3000 = 0
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document.write( "factor
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document.write( "(x + 60)(x-50) = 0
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document.write( "x + 60)= 0  x = -60 cannot use
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document.write( "(x-50) = 0  x = 50mph her old speed.  Her new speed would be 60mph( 10mph faster) \n" );
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