document.write( "Question 43354: Julie's whaler cruised 45 miles upstream and 45 miles back in a total of 8 hr. the speed of the river is 3mph. Find the speed of the boat in still water.\r
\n" ); document.write( "\n" ); document.write( "having problems setting this up \n" ); document.write( "
Algebra.Com's Answer #28375 by stanbon(75887)\"\" \"About 
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Julie's whaler cruised 45 miles upstream and 45 miles back in a total of 8 hr. the speed of the river is 3mph. Find the speed of the boat in still water.
\n" ); document.write( "Let the speed of the boat in still water be \"b\"
\n" ); document.write( "Upstream DATA:
\n" ); document.write( "distance= 45; rate=b-3;time=d/r=45/(b-3)\r
\n" ); document.write( "\n" ); document.write( "Downstream DATA:
\n" ); document.write( "distance= 45; rate=b+3; time=d/r=45/(b+3)\r
\n" ); document.write( "\n" ); document.write( "EQUATION:
\n" ); document.write( "Time Up + Time Down = 8 hrs.
\n" ); document.write( "45/(b-3) + 45(b+3)= 8\r
\n" ); document.write( "\n" ); document.write( "45(b+3) + 45(b-3)=8(b^2-9)
\n" ); document.write( "90b=8b^2-72
\n" ); document.write( "8b^2-90b-72=0
\n" ); document.write( "4b^2-45b-36=0
\n" ); document.write( "b=[45-sqrt(45^2-4(4)(-36)]/8=[45-38.0657]/8=0.86678... mph
\n" ); document.write( "OR
\n" ); document.write( "b=[45+sqrt(45^2-4(4)(-36)]/8=[45+38.0657]/8=10.3832... mph\r
\n" ); document.write( "\n" ); document.write( "Cheers,
\n" ); document.write( "stan H. \n" ); document.write( "
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