document.write( "Question 831798: Tinh can row at a rate of 6 mph in still water. It takes her 2 hours to row upstream from a dock to a park. She then rows back to the dock, and it only takes 40 minutes. What is the speed of the river current? \n" ); document.write( "
Algebra.Com's Answer #501651 by josgarithmetic(39620)\"\" \"About 
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c = speed of the current.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "_______________speed_______________time_____________distance
\n" ); document.write( "UP_____________6-c_________________2__________________d
\n" ); document.write( "DOWN___________6+c_________________2/3________________d\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Same distance each way. Rate*Time gives the distance, and both expressions must be equal.
\n" ); document.write( "Forty minutes is the same as (2/3) hour. We can keep all in miles and hours.\r
\n" ); document.write( "\n" ); document.write( "\"%286-c%29%2A2=%286%2Bc%29%282%2F3%29\"
\n" ); document.write( "Simplify and solve for c.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2%2A3%286-c%29=2%286%2Bc%29\"
\n" ); document.write( "\"3%286-c%29=%286%2Bc%29\"
\n" ); document.write( "\"18-3c=c%2B6\"
\n" ); document.write( "\"18=c%2B3c%2B6\"
\n" ); document.write( "\"4c=12\"
\n" ); document.write( "RESULT: \"c=3\" mph
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