document.write( "Question 941218: A car travels 20km / h faster than a cyclist. The car takes one hour less than the cyclist to travel 150 km. Assuming the speed of the car is x km/h
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document.write( "a) write down in terms of x expressions for the time takrn by the car and the cyclist
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document.write( "B) form a quadratic equation to connect these times
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document.write( "C) SOLVE the equation to find the speed of the car and the cyclist \n" );
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Algebra.Com's Answer #573776 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! A car travels 20km / h faster than a cyclist. \n" ); document.write( " The car takes one hour less than the cyclist to travel 150 km. \n" ); document.write( " Assuming the speed of the car is x km/h \n" ); document.write( "a) write down in terms of x expressions for the time taken by the car and the cyclist \n" ); document.write( "Car time: \n" ); document.write( ": \n" ); document.write( "B) form a quadratic equation to connect these times \n" ); document.write( " Cyclist time - car time = 1 hr \n" ); document.write( " \n" ); document.write( "multiply equation by x(x-20) \n" ); document.write( "x(x-20)* \n" ); document.write( "Cancel the denominators and we have \n" ); document.write( "150x - 150(x-20) = x^2 - 20x \n" ); document.write( "150x - 150x + 3000 = x^2 - 20x \n" ); document.write( "combine to form a quadratic equation on right \n" ); document.write( "f(x) = x^2 - 20x - 3000 \n" ); document.write( ": \n" ); document.write( "C) SOLVE the equation to find the speed of the car and the cyclist \n" ); document.write( "x^2 - 20x - 3000 = 0 \n" ); document.write( "Use the quadratic formula; a=1; b=-20; c=-3000 \n" ); document.write( "I got a positive rounded off solution of: \n" ); document.write( "x = 65.68 is speed of the car \n" ); document.write( "and \n" ); document.write( "45.68 km/hr is the speed of the cyclist (20 km/hr less) \n" ); document.write( ": \n" ); document.write( "Check this by finding the actual time of each \n" ); document.write( "Cyclist: 150/45.68 = 3.28 hrs \n" ); document.write( "Car: 150/65.68 = 2.28 hrs, \n" ); document.write( " |