document.write( "Question 1176815: A motorboat travels 165 kilometers in 3 hours going upstream. It travels 207 kilometers going downstream in the same amount of time. What is the rate of the boat in still water and what is the rate of the current? \n" ); document.write( "

Algebra.Com's Answer #804544 by mananth(16946) $\"\"$ $\"About$

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let rate of the boat in still water be x km/h
\n" ); document.write( " and the rate of the current be y km/h\r
\n" ); document.write( "\n" ); document.write( "Upstream speed = x-y\r
\n" ); document.write( "\n" ); document.write( "Time = D/S\r
\n" ); document.write( "\n" ); document.write( "165/(x-y) = 3
\n" ); document.write( "3x-3y=165 -----------(1)\r
\n" ); document.write( "\n" ); document.write( "Downstream speed = x+y
\n" ); document.write( "207/(x+y) =3
\n" ); document.write( "3x+3y= 207-----------(2)\r
\n" ); document.write( "\n" ); document.write( "Add equations (1) & (2)
\n" ); document.write( "6x=207+165
\n" ); document.write( "6x = 372
\n" ); document.write( "x= 62
\n" ); document.write( " speed of boat in still water= 62 km/h
\n" ); document.write( "Plug x to get y\r
\n" ); document.write( "\n" ); document.write( "3x-3y=165
\n" ); document.write( "186-3y =165\r
\n" ); document.write( "\n" ); document.write( "3y= 21
\n" ); document.write( "y=7\r
\n" ); document.write( "\n" ); document.write( "Speed of current is 7 km/h\r
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