document.write( "Question 312076: Ride the peaks. Smith bicycled 45 miles going east from
\n" );
document.write( "Durango, and Jones bicycled 70 miles. Jones averaged
\n" );
document.write( "5 miles per hour more than Smith, and his trip took one-half
\n" );
document.write( "hour longer than Smith’s. How fast was each one traveling? \n" );
document.write( "
Algebra.Com's Answer #223309 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! Smith bicycled 45 miles going east from Durango, and Jones bicycled 70 miles. \n" ); document.write( " Jones averaged 5 miles per hour more than Smith, and his trip took one-half \n" ); document.write( "hour longer than Smith’s. \n" ); document.write( " How fast was each one traveling? \n" ); document.write( ": \n" ); document.write( "Let s = Smith's speed \n" ); document.write( "then \n" ); document.write( "(s+5) = Jone's speed \n" ); document.write( ": \n" ); document.write( "Write a time equation, Time = dist/speed \n" ); document.write( ": \n" ); document.write( "Jones time - Smiths time = .5 hr \n" ); document.write( " \n" ); document.write( "multiply by s(s+5), results: \n" ); document.write( "70s - 45(s+5) = .5s(s+5) \n" ); document.write( ": \n" ); document.write( "70s - 45s - 225 = .5s^2 + 2.5s \n" ); document.write( "25s - 225 = .5s^2 + 2.5s \n" ); document.write( "combine on the right \n" ); document.write( "0 = .5s^2 + 2.5s - 25s + 225 \n" ); document.write( "A quadratic equation \n" ); document.write( ".5s^2 - 22.5s + 225 = 0 \n" ); document.write( "Get rid of th decimals, mult by 2 \n" ); document.write( "s^2 - 45s + 450 = 0 \n" ); document.write( "Factors to \n" ); document.write( "(s-15)(s-30) = 0 \n" ); document.write( "Two solutions \n" ); document.write( "s = 15 mph is Smith's time, then Jones time = 20 mph \n" ); document.write( "and \n" ); document.write( "s = 30 mph is Smith's time, then Jones time = 35 \n" ); document.write( ": \n" ); document.write( "The slower time would make more sense for bicycle \n" ); document.write( "Check by finding the times \n" ); document.write( "70/20 = 3.5 \n" ); document.write( "45/15 = 3.0 \n" ); document.write( "------------ \n" ); document.write( "differ: .5h \n" ); document.write( " \n" ); document.write( " |