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.
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\n" ); document.write( "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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Let speed on 1st part of trip be S
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document.write( "Then time taken to travel 60 km = 
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document.write( "On the 2nd part of trip, a 15 km/h increase in speed results in a speed of S + 15
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document.write( "Then time taken to travel the remaining 40 (100 - 60) km is: 
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document.write( "Since total time was 2 hours, then we can say that:
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document.write( "60(S + 15) + 40S = 2(S)(S + 15) ------- Multiplying by LCD, S(S + 15)
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document.write( "(S - 45)(S + 10) = 0
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document.write( "S, or speed on 1st part of trip =  km/h			OR			S = - 10 (ignore)
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document.write( "Speed on 2nd part of trip: 45 + 15, or  km/h \n" );
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