document.write( "Question 141890: I refer to question number 139334 and question number 139296, both answerd by stanbon.\r
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\n" ); document.write( "\n" ); document.write( "It takes Boat A 3 hours longer to travel 50kms than it takes Boat B to travel 60kms. Boat A travels one third the speed of Boat B. What is the speed of each boat.
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\n" ); document.write( "A-Boat DATA:
\n" ); document.write( "distance 50 km ; Rate = x kph ; time = 50/x
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\n" ); document.write( "B-Boat DATA:
\n" ); document.write( "distance = 60 km ; rate = 3x kph ; time = 60/(3x)
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\n" ); document.write( "EQUATION:
\n" ); document.write( "time A - time B = 3
\n" ); document.write( "50/x - 60/(3x) = 3
\n" ); document.write( "Multiply thru by 3x to get
\n" ); document.write( "150 - 60 = 9x
\n" ); document.write( "90 = 9x
\n" ); document.write( "x = 10 kph (speed of A-Boat)
\n" ); document.write( "3x = 30 kph (speed of B-Boat)
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\n" ); document.write( "\n" ); document.write( "It takes a cabin cruiser 3 hours longer to travel 50kms than it takes a power boat to travel 60kms. The cruiser travels one third the speed of the power boat. Find the speed of each boat.
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\n" ); document.write( "Cruiser DATA:
\n" ); document.write( "distance = 50 km ; rate = x kph ; time = 50/x hrs
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\n" ); document.write( "Power Boat DATA:
\n" ); document.write( "distance = 60 km ; rate = 3x kph ; time = 60/(3x) hrs
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\n" ); document.write( "EQUATION:
\n" ); document.write( "cruise time = power boat time + 3 hrs.
\n" ); document.write( "50/x = 60/3x + 3
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\n" ); document.write( "Multiply thru by 3x to get:
\n" ); document.write( "150 = 60 + 9x
\n" ); document.write( "210 = 9x
\n" ); document.write( "x = 70/3 = 23 1/3 kph (cruiser speed)
\n" ); document.write( "3x = 70 kph (power boat speed)
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\n" ); document.write( "\n" ); document.write( "The questions are identical, save for the description of the boats, yet the answers are different.\r
\n" ); document.write( "\n" ); document.write( "Please confirm the answer to the second question is correct ...... I would have thought the equation should have read:\r
\n" ); document.write( "\n" ); document.write( "Multiply thru by 3x to get:
\n" ); document.write( "150 = 60 + 9x
\n" ); document.write( "90 = 9x
\n" ); document.write( "x = 90/9 = 10 kph (cruiser speed)
\n" ); document.write( "3x = 10*3 = 30 kph (power boat speed)\r
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\n" ); document.write( "\n" ); document.write( "Thanks\r
\n" ); document.write( "\n" ); document.write( "George
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Algebra.Com's Answer #103363 by ptaylor(2198)\"\" \"About 
You can put this solution on YOUR website!
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( "Let r=rate (speed) of Boat B
\n" ); document.write( "Then r/3=speed of Boat A\r
\n" ); document.write( "\n" ); document.write( "Time required for boat B to travel 60 km=60/r
\n" ); document.write( "Time required for Boat A to travel 50 km=50/(r/3)=150/r\r
\n" ); document.write( "\n" ); document.write( "And we are told that Boat A's time is 3 hours longer than Boat B's time, so:\r
\n" ); document.write( "\n" ); document.write( "150/r=(60/r)+3 multiply each term by r\r
\n" ); document.write( "\n" ); document.write( "150=60+3r subtract 60 from each side
\n" ); document.write( "150-60=60-60+3r collect like terms
\n" ); document.write( "90=3r divide each side by 3
\n" ); document.write( "r=30 km/h----------------------------------------speed of Boat B\r
\n" ); document.write( "\n" ); document.write( "r/3=30/3=10 km/h----------------------------------speed of Boat A\r
\n" ); document.write( "\n" ); document.write( "CK
\n" ); document.write( "50/10=60/30+3
\n" ); document.write( "5=2+3
\n" ); document.write( "5=5\r
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\n" ); document.write( "\n" ); document.write( "Hope this helps---ptaylor
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