document.write( "Question 696828: The speed of the boat in still water is 15km/hr.It can go 30 km upstream and return to down stream in 41/2hrs.find the speed of the stream. \n" ); document.write( "
Algebra.Com's Answer #429422 by lwsshak3(11628)\"\" \"About 
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The speed of the boat in still water is 15km/hr.It can go 30 km upstream and return to down stream in 41/2hrs.find the speed of the stream.
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\n" ); document.write( "let x=speed of stream
\n" ); document.write( "(15+x)=speed of boat downstream
\n" ); document.write( "(15-x)=speed of boat upstream
\n" ); document.write( "travel time=distance/speed
\n" ); document.write( "30/(15+x)+30/(15-x)=9/2
\n" ); document.write( "60/(15+x)+60/(15-x)=9
\n" ); document.write( "LCD: (15+x)(15-x)
\n" ); document.write( "60(15-x)+60(15+x)=9(15+x)(15-x)
\n" ); document.write( "60(15-x+15+x)=9(225-x^2)
\n" ); document.write( "60(30)=2025-9x2
\n" ); document.write( "9x^2=2025-1800
\n" ); document.write( "9x2=225
\n" ); document.write( "take sqrt of both sides
\n" ); document.write( "3x=15
\n" ); document.write( "x=5
\n" ); document.write( "speed of stream=5 km/hr\r
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