document.write( "Question 1071927: A car traveled 1950 mi at a certain speed. If the speed had been 13 mph faster, the trip could have been made in 5 hr less time. Find the speed. \n" ); document.write( "

Algebra.Com's Answer #686840 by ikleyn(52788) $\"\"$ $\"About$

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document.write( "Let r\" be the actual speed, in mph.\r\n" );
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document.write( "Then the hypothetical speed is (r+13) mph.\r\n" );
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document.write( "Moving at the speed of \"r\" miles per hour, the car spends  hours.\r\n" );
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document.write( "Traveling with the hypothetical speed, the car would spend  hours.\r\n" );
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document.write( "The condition says\r\n" );
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document.write( " = 5.\r\n" );
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document.write( "It is your \"time\" equation.  You must solve it for \"r\". \r\n" );
document.write( "To do it, multiply both sides by the common denominator r*(r+13). You will get\r\n" );
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document.write( "1950*(r+13) - 1950*r = 5r*(r+13),\r\n" );
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document.write( " = ,\r\n" );
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document.write( " = 0.\r\n" );
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document.write( "Factor it:\r\n" );
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document.write( "(r+78)*(r-65) = 0.\r\n" );
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document.write( "The only positive root is r = 65.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Answer. The speed of the car is 65 mph.\r
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