document.write( "Question 164547: First tourist walked a distance of 30 km in a time 10 minutes shorter than the second tourist. Calculate their speeds if the speed of the first one was 3 km/h greater than that of the second one. \n" ); document.write( "
Algebra.Com's Answer #121286 by ptaylor(2198)\"\" \"About 
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First tourist walked a distance of 30 km in a time 10 minutes shorter than the second tourist. Calculate their speeds if the speed of the first one was 3 km/h greater than that of the second one.\r
\n" ); document.write( "\n" ); document.write( "Distance(d) equals Rate(r) times Time(t) or d=rt; r=d/t and t=d/r\r
\n" ); document.write( "\n" ); document.write( "Since the problem is dealing in both hours and minutes, we'll just keep it simple and deal in hours
\n" ); document.write( "Let t=time it took second tourist to walk 30km
\n" ); document.write( "Then t-(1/6)=time it took first tourist to walk 30 km
\n" ); document.write( "Rate (speed) of second tourist=30/t
\n" ); document.write( "Rate of first tourist=30/(t-(1/6)) and we are told that this is 3 km/hr greater than the speed of the second tourist, so our equation to solve is\r
\n" ); document.write( "\n" ); document.write( "(30/(t-(1/6)))-3=30/t multiply each term by t(t-(1/6))
\n" ); document.write( "30t-3t(t-(1/6))=30(t-(1/6)) get rid of parens (distributive law)\r
\n" ); document.write( "\n" ); document.write( "30t-3t^2+0.5t=30t-5 subtract 30t from and also add 5 to both sides
\n" ); document.write( "30t-30t-3t^2+0.5t+5=30t-30t-5+5 collect like terms
\n" ); document.write( "-3t^2+0.5t+5=0 multiply each term by -1
\n" ); document.write( "3t^2-0.5t-5=0 Quadratic in standard form; solve using the quadratic formula
\n" ); document.write( "\"t+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "\"t+=+%280.5+%2B-+sqrt%28+0.25-4%2A3%2A%28-5%29+%29%29%2F%286%29+\"
\n" ); document.write( "\"t+=+%280.5+%2B-+sqrt%2860.25%29%29%2F%286%29+\"
\n" ); document.write( "\"t+=+%280.5+%2B-7.76%29%2F%286%29+\"
\n" ); document.write( "\"t+=+%280.5+%2B7.76%29%2F%286%29+\"
\n" ); document.write( "\"t+=+%288.26%29%2F%286%29+\"
\n" ); document.write( "\"t+=+1.377\" hrs----time it took second tourist
\n" ); document.write( "\"t-%281%2F6%29=t-0.167=1.377-0.677=1.21\" hrs-----time it took first tourist
\n" ); document.write( "rate of second tourist=30/1.377=21.8 km/hr--------------------ans
\n" ); document.write( "rate of first tourist=30/1.21=24.8 km/hr------------------------ans\r
\n" ); document.write( "\n" ); document.write( "\"t+=+%280.5+-7.76%29%2F%286%29+\" --------------disregard the negative value for t\r
\n" ); document.write( "\n" ); document.write( "Hope this helps----ptaylor
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