document.write( "Question 759443: felix rode 18 miles downstrem and back to the same place where he started, in 3 hours and 12 minutes. find the rate of felix in still water if the velocity of the stream is 3 miles per hour \n" ); document.write( "

Algebra.Com's Answer #462055 by lwsshak3(11628) $\"\"$ $\"About$

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felix rode 18 miles downstrem and back to the same place where he started, in 3 hours and 12 minutes. find the rate of felix in still water if the velocity of the stream is 3 miles per hour.
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\n" ); document.write( "let x=rate of Felix in still water
\n" ); document.write( "x+3=rate downstream
\n" ); document.write( "x-3=rate upstream
\n" ); document.write( "travel time=distance/rate
\n" ); document.write( "3hr and 12 min=16/5 hrs
\n" ); document.write( " $\"18%2F%28x%2B3%29%2B18%2F%28x-3%29=16%2F5\"$
\n" ); document.write( "LCD:5(x+3)(x-3)
\n" ); document.write( " $\"5%2A18%2A%28x-3%29%2B5%2A18%2A%28x%2B3%29=16%28x-3%29%28x%2B3%29\"$
\n" ); document.write( " $\"90x-270%2B90x%2B270=16x%5E2-144\"$
\n" ); document.write( "16x^2-180x-144=0
\n" ); document.write( "4x^2-45x-36=0
\n" ); document.write( "(4x+3)(x-12)=0
\n" ); document.write( "x=-3/4 (reject, x>0)
\n" ); document.write( "or
\n" ); document.write( "x=12
\n" ); document.write( "rate of Felix in still water=12 mph
\n" ); document.write( " \n" ); document.write( "

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