document.write( "Question 192908: The excursion boat on the river takes 2½ hours to make the trip to a point 12 miles upstream and to return. If the rate at which the boat travels in still water is 5 times the rate of the river current, what is the rate of the current? \n" ); document.write( "
Algebra.Com's Answer #144791 by stanbon(75887)\"\" \"About 
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The excursion boat on the river takes 2½ hours to make the trip to a point 12 miles upstream and to return. If the rate at which the boat travels in still water is 5 times the rate of the river current, what is the rate of the current?
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\n" ); document.write( "Let the current speed be \"c\";
\n" ); document.write( "Then the boat speed in still wate is \"5c\":
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\n" ); document.write( "Upstream speed:
\n" ); document.write( "distance = 12 miles ; rate = 5c-c = 4c mph ; time = 12/4c = 3/c hrs
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\n" ); document.write( "Downstream speed:
\n" ); document.write( "distance = 12 miles ; rate = 5c+c = 6c mph ; time = 12/6c = 2/c hrs
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\n" ); document.write( "Equation:
\n" ); document.write( "time + time = 2 1/2 hrs
\n" ); document.write( "3/c + 2/c = 5/2
\n" ); document.write( "Multiply thru by 2c to get:
\n" ); document.write( "6 + 4 = 5c
\n" ); document.write( "c = 2 mph (speed of the current)
\n" ); document.write( "5c = 10 mph (speed of the boat in still water)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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