document.write( "Question 258761: jacqui commutes 30 miles to her job each day. She finds that if she drives 10 miles/hour faster, it takes her 6 minutes less to get to work .find her new speed \n" ); document.write( "

Algebra.Com's Answer #190483 by stanbon(75887) $\"\"$ $\"About$

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jacqui commutes 30 miles to her job each day. She finds that if she drives 10 miles/hour faster, it takes her 6 minutes less to get to work.
\n" ); document.write( "find her new speed
\n" ); document.write( "------------------------
\n" ); document.write( "Old DATA:
\n" ); document.write( "distance = 30 miles ; rate = x mph ; time = d/r = 30/x hrs.
\n" ); document.write( "--------------------------------------------------
\n" ); document.write( "New DATA:
\n" ); document.write( "distance = 30 miles ; rate = (x+10) mph ; time = d/r = 30/(x+10) hrs
\n" ); document.write( "------------------------------------------------------
\n" ); document.write( "Equation:
\n" ); document.write( "old time - new time = 1/10 hr
\n" ); document.write( "30/x - 30/(x+10) = 1/10
\n" ); document.write( "Multiply thru by 10x(x+10)
\n" ); document.write( "300(x+10) - 300x = x(x+10)
\n" ); document.write( "3000 = x^2 + 10x
\n" ); document.write( "---
\n" ); document.write( "x^2 + 10x - 3000 = 0
\n" ); document.write( "(x+60)(x-50) = 0
\n" ); document.write( "---
\n" ); document.write( "Positive solution:
\n" ); document.write( "x = 50 mph (old speed)
\n" ); document.write( "---
\n" ); document.write( "x+10 = 60 mph (her new speed)
\n" ); document.write( "==================================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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