document.write( "Question 1111808: I have to walk a distance of 24km. If I increase my usual rate of walking by 2km/h, I can reduce the time taken by 1 hour.
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document.write( "a) find my usual rate of walking
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document.write( "b) if I can reduce my usual rate of walking by 2km/ h, how long does it take me to walk 24km? \n" );
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Algebra.Com's Answer #726825 by ikleyn(52781)![]() ![]() You can put this solution on YOUR website! . \n" ); document.write( " \r\n" ); document.write( "Let \"r\" be your usual rate, and t be the time to walk 24 km at this rate.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "Then\r\n" ); document.write( "\r\n" ); document.write( "rt = 24 (1)\r\n" ); document.write( "(r+2)*(t-1) = 24. (2)\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "Transform eq(2) in this way:\r\n" ); document.write( "\r\n" ); document.write( "rt + 2t - r - 2 = 24. (3)\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "Take into account that 24 = rt in accordance with (1). So you can cancel the terms rt and 24 in both sides of the equation (3) to get\r\n" ); document.write( "\r\n" ); document.write( "2t - r - 2 = 0, or simply r = 2t-2 = 2*(t-1).\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "Next substitute this expression for r, r = 2*(t-1), into eq(1) to get\r\n" ); document.write( "\r\n" ); document.write( "2(t-1)*t = 24, or t*(t-1) = 12.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "Further, you can solve the last equation for t as a quadratic equation, or simply \"to guess\" the solution t = 4.\r\n" ); document.write( "\r\n" ); document.write( "\r\n" ); document.write( "So, the answer to the question a) is t = 4 hours (your usual time) and r =\r \n" ); document.write( "\n" ); document.write( "Solved.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-------------- \n" ); document.write( "To see other similar solved problems, look into the lesson\r \n" ); document.write( "\n" ); document.write( " - Had a car move faster it would arrive sooner\r \n" ); document.write( "\n" ); document.write( "in this site.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |