document.write( "Question 819775: A boat takes 1.5 hour to go 12 miles upstream against the current. It can go 24 miles downstream with the current in the same amount of time. Find the speed of the current and the speed of the boat in still water. \n" ); document.write( "

Algebra.Com's Answer #493205 by josgarithmetic(39625) $\"\"$ $\"About$

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r, speed of boat without any current
\n" ); document.write( "c, speed of current\r
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\n" ); document.write( "\n" ); document.write( "WhichWay______speed_________time________________distance
\n" ); document.write( "Up____________r-c___________12/(r-c)_____________12
\n" ); document.write( "Down__________r+c___________24/(r+c)_____________24\r
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\n" ); document.write( "\n" ); document.write( "The times are equal, according to given description.
\n" ); document.write( "We also know r-c=1.5, also based on given description.\r
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\n" ); document.write( "\n" ); document.write( "We have two equations:
\n" ); document.write( " $\"highlight_green%28r-c=1.5%29\"$ and $\"highlight_green%2812%2F%28r-c%29=24%2F%28r%2Bc%29%29\"$
\n" ); document.write( "Solve for r and c.\r
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\n" ); document.write( "\n" ); document.write( "Actually there is something else you could do.
\n" ); document.write( "Knowing $\"r-c=1.5\"$ , use this for the upstream information, the time is $\"12%2F%281.5%29=8\"$ hours. This is also supposed to be the downstream time for the 24 mile distance.
\n" ); document.write( "Now you could say $\"12%2F%28r-c%29=8\"$ and $\"24%2F%28r%2Bc%29=8\"$ and solve these two equations for r and c. \n" ); document.write( "

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