Algebra.Com's Answer #801885 by ikleyn(52779)![\"\"](\"/images/stars/stars-13.gif\")  
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document.write( "Peter travels from his place to his uncle house a distance of 30km.He cycles for two thirds of the journey
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document.write( "before walking for the rest of the journey. If his cycling speed is 10km/hr more than the walking speed
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document.write( "and the whole journey took him 3hrs 20 minutes, calculate his cycling speed.
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document.write( "Let x be his cycling speed in km/h; then his walking speed was (x-10) km/h.\r\n" );
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document.write( "He cycled 20 km at the speed x km/h --- hence, he spent  hours for this part of the journey.\r\n" );
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document.write( "He walked 10 km at the speed (x-10) km/h --- hence, he spent  hours for this part of the journey.\r\n" );
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document.write( "The total time was 3 hours 20 minutes = 3  hours =  hours.\r\n" );
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document.write( "It gives you this \"time equation\"\r\n" );
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document.write( " + = . (1)\r\n" );
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document.write( "To solve it, multiply both sides by 3\r\n" );
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document.write( "  +  = 10. (2)\r\n" );
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document.write( "At this point, you just can easily guess the solution MENTALLY: it is x= 15 km/h.\r\n" );
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document.write( "Alternatively, you may reduce equation (1) or (2) to the standard form quadratic equation and solve it formally.\r\n" );
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document.write( "ANSWER. His cycling speed is 15 km/h.\r\n" );
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document.write( "CHECK. I will check equation (1) :  = 1 + 2 = 3 + hours. ! Correct !\r\n" );
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document.write( "Solved.\r
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