document.write( "Question 376588: During the first part of a trip, a canoeist travels 71 miles at a certain speed. The canoeist travels 12 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 5 hours. What was the speed on EACH part of the trip? \n" ); document.write( "
Algebra.Com's Answer #267955 by ankor@dixie-net.com(22740)\"\" \"About 
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During the first part of a trip, a canoeist travels 71 miles at a certain speed.
\n" ); document.write( " The canoeist travels 12 miles on the second part of the trip at a speed 5 mph slower.
\n" ); document.write( " The total time for the trip is 5 hours. What was the speed on EACH part of the trip?
\n" ); document.write( ":
\n" ); document.write( "Let s = speed for the 1st part of the trip
\n" ); document.write( "then
\n" ); document.write( "(s-5) = speed on the 2nd part of the trip
\n" ); document.write( ":
\n" ); document.write( "Write time equation; time = dist/speed
\n" ); document.write( ":
\n" ); document.write( "1st speed time + 2nd speed time = 5 hrs
\n" ); document.write( "\"71%2Fs\" + \"12%2F%28%28s-5%29%29\" = 5
\n" ); document.write( "Multiply by s(s-5) to clear the denominators, results:
\n" ); document.write( "71(s-5) + 12s = 5s(s-5)
\n" ); document.write( "71s - 355 + 12s = 5s^2 - 25s
\n" ); document.write( "83s - 355 = 5s^2 - 25s
\n" ); document.write( "0 = 5s^2 - 25s - 83s + 355
\n" ); document.write( "5s^2 - 108s + 355 = 0
\n" ); document.write( "Use the quadratic formula to find s
\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "Where x = s; a=5; b=-108; c=355
\n" ); document.write( "\"s+=+%28-%28-108%29+%2B-+sqrt%28-108%5E2-4%2A5%2A355+%29%29%2F%282%2A5%29+\"
\n" ); document.write( ":
\n" ); document.write( "\"s+=+%28108+%2B-+sqrt%2811664-7100+%29%29%2F10+\"
\n" ); document.write( ":
\n" ); document.write( "\"s+=+%28108+%2B-+sqrt%284564+%29%29%2F10+\"
\n" ); document.write( "two solutions
\n" ); document.write( "\"s+=+%28108+%2B+67.557%29%2F10+\"
\n" ); document.write( "s = \"175.557%2F10\"
\n" ); document.write( "s = 17.5557
\n" ); document.write( "and
\n" ); document.write( "\"s+=+%28108+-+67.557%29%2F10+\"
\n" ); document.write( "s = \"40.443%2F10\"
\n" ); document.write( "s = 4.0443
\n" ); document.write( ":
\n" ); document.write( "s = 17.5557 mph is the only reasonable speed for the 1st part of the trip
\n" ); document.write( "and
\n" ); document.write( "17.5557 - 5 = 12.5557 mph is the speed on the 2nd part of the trip
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "See if this is true, find the time at each speed
\n" ); document.write( "71/17.5557 = 4.044 hrs
\n" ); document.write( "12/12.5557 = .9557
\n" ); document.write( "-------------------
\n" ); document.write( "total time: 4.9997 ~ 5 hrs
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