document.write( "Question 970277: Colton went on a bike ride of 36 miles. He realized that if he had gone 3 mph faster, he would have arrived 6 hours sooner. How fast did he actually ride?
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Algebra.Com's Answer #592933 by ankor@dixie-net.com(22740) You can put this solution on YOUR website! Colton went on a bike ride of 36 miles. \n" ); document.write( " He realized that if he had gone 3 mph faster, he would have arrived 6 hours sooner. \n" ); document.write( " How fast did he actually ride? \n" ); document.write( ": \n" ); document.write( "let s = actual speed \n" ); document.write( "then \n" ); document.write( "(s+3) = the faster time speed \n" ); document.write( ": \n" ); document.write( "Write a time equation, time = dist/speed \n" ); document.write( ": \n" ); document.write( "Actual time - faster time = 6 hrs \n" ); document.write( " \n" ); document.write( "multiply equation by s(s+3) \n" ); document.write( "s(s+3)* \n" ); document.write( "cancel the denominators \n" ); document.write( "36(s+3) - 36s = 6s^2 + 18s \n" ); document.write( "36s + 108 - 36s = 6s^2 + 18s \n" ); document.write( "Combine as a quadratic equation on the right \n" ); document.write( "0 = 6s^2 + 18s - 108 \n" ); document.write( "simplify, divide by 6 \n" ); document.write( "s^2 + 3s - 18 = 0 \n" ); document.write( "Factors to \n" ); document.write( "(s + 6)(s - 3) = 0 \n" ); document.write( "the positive solution is all we want here \n" ); document.write( "s = 3 mph his actual speed \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check this find the actual time at each speed \n" ); document.write( "36/3 = 12 hrs \n" ); document.write( "36/6 = 6 hrs; 6 hrs faster\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |