document.write( "Question 392246: sir pls help me to solve this prblm.A train travels at a certain average for a didtance of 63km and then travels a distance of 72km at an average speed of 6km/hr more than its original speed.if it takes 3 hours to complete the total journey,what is its original average speed.kindly send me the solution to rexi_2004@yahoo.co.in \n" ); document.write( "

Algebra.Com's Answer #278416 by ewatrrr(24785) $\"\"$ $\"About$

You can put this solution on YOUR website!


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document.write( "Hi
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document.write( "Let x and (x + 6kmph) represent the speeds traveling 63km and 72km respectively
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document.write( "Question States***total time of trip 3hr.  t = D/r
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document.write( " 63/x  + 72/(x+6) = 3  |Multiplying each term by x(x+6) so as all denominators= 1
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document.write( " 63(x+6) + 72x = 3x(x+6)
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document.write( " 63x + 6*63 + 72x = 3x^2 + 18x
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document.write( "   3x^2 -117x - 378 = 0
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document.write( "  3(x^2 - 39x - 126) = 0
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document.write( "factoring
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document.write( "  (x+3)(x-42) = 0
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document.write( "  (x+3) = 0   |tossing out negative solution
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document.write( "  (x-42) = 0
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document.write( "    x = 42kmph, speed of train while traveling 63kmph, the original average speed\r
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document.write( "CHECKING our Answer ***
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document.write( "  63km/42kmph + 72km/48kmph = 1.5hr + 1.5hr =  3hr
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