document.write( "Question 982361: On a journey of 100km, Jim travels at a certain speed for the first 60km, and then increases his speed by 15km/h for the remainder. If the whole journey takes 2 hours, find his two speeds.
\n" ); document.write( "I'm in year 10, and this is an A-standard question which neither of my parents nor I could solve.
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Algebra.Com's Answer #603178 by josgarithmetic(39630)\"\" \"About 
You can put this solution on YOUR website!
Uniform Rates for Travel, RT=D relates rate, time, distance.\r
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\n" ); document.write( "\n" ); document.write( "Let r be the unknown rate for the first part;
\n" ); document.write( "let d be the unknown distance of the second part;\r
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\n" ); document.write( "\n" ); document.write( "___________________rate_____________time_____________distance
\n" ); document.write( "part1_______________r_______________(___)_____________60
\n" ); document.write( "part2______________r+15_____________(___)_____________d
\n" ); document.write( "TOTALS_______________________________2________________100\r
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\n" ); document.write( "\n" ); document.write( "Form expressions for the missing time quantities from the basic idea \"RT=D\",
\n" ); document.write( "\"RT%2FR=D%2FR\"
\n" ); document.write( "\"highlight_green%28T=D%2FR%29\"\r
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\n" ); document.write( "\n" ); document.write( "___________________rate_____________time_____________distance
\n" ); document.write( "part1_______________r_______________60/r______________60
\n" ); document.write( "part2______________r+15_____________d/(r+15)___________d
\n" ); document.write( "TOTALS_______________________________2________________100\r
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\n" ); document.write( "\n" ); document.write( "Note that the distance sum arrangement will give the unknown part2 distance.
\n" ); document.write( "60+d=100
\n" ); document.write( "d=100-60
\n" ); document.write( "d=40
\n" ); document.write( "and you can adjust the tabulated information:\r
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\n" ); document.write( "\n" ); document.write( "___________________rate_____________time_____________distance
\n" ); document.write( "part1_______________r_______________60/r______________60
\n" ); document.write( "part2______________r+15_____________40/(r+15)__________40
\n" ); document.write( "TOTALS_______________________________2________________100\r
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\n" ); document.write( "\n" ); document.write( "The total time will give an equation in the single variable, r.
\n" ); document.write( "\"60%2Fr%2B40%2F%28r%2B15%29=2\"
\n" ); document.write( "This can be partly simplified to
\n" ); document.write( "\"%2860%2Fr%2B40%2F%28r%2B15%29%29%281%2F2%29=2%281%2F2%29\"
\n" ); document.write( "\"highlight_green%2830%2Fr%2B20%2F%28r%2B15%29=1%29\"\r
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\n" ); document.write( "\n" ); document.write( "Can you solve this equation for r ?\r
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\n" ); document.write( "\n" ); document.write( "---
\n" ); document.write( "The algebra steps give a factorable quadratic equation, making the final answer apparent.
\n" ); document.write( "\"highlight%28highlight%28r=45%29%29\"
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