document.write( "Question 110987: Kelley's boat goes 12mph. Find the rate of the cureent of the river if she can go 6mi upstream in the same amount of time she can go 10mi downstream. \n" ); document.write( "

Algebra.Com's Answer #80989 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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Kelley's boat goes 12 mph. Find the rate of the current of the river, if she can go 6 mi upstream in the same amount of time she can go 10 mi downstream.
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\n" ); document.write( "Let x = rate of the currents
\n" ); document.write( "Then:
\n" ); document.write( "(12+x) = speed downstream
\n" ); document.write( "and
\n" ); document.write( "(12-x) = speed upstream
\n" ); document.write( ":
\n" ); document.write( "Time = Dist/speed
\n" ); document.write( ":
\n" ); document.write( "Up time = down time
\n" ); document.write( " $\"6%2F%2812-x%29\"$ = $\"10%2F%2812%2Bx%29\"$
\n" ); document.write( ":
\n" ); document.write( "Cross multiply:
\n" ); document.write( "6(12+x) = 10(12-x)
\n" ); document.write( ":
\n" ); document.write( "72 + 6x = 120 - 10x
\n" ); document.write( ":
\n" ); document.write( "6x + 10x = 120 - 72
\n" ); document.write( "16x = 48
\n" ); document.write( "x = 48/16
\n" ); document.write( "x = 3 mph speed of the current
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solution by confirming the times are the same:
\n" ); document.write( "10/15 = 2/3 hr
\n" ); document.write( "6/9 = 2/3 hr \n" ); document.write( "

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