document.write( "Question 522971: After sailing 15 miles a boat changed direction and increased speed by 2 mph. At this 2 mile faster speed an additional 19 miles was traveled. The total travel time was 4 hours. What is the rate of the boat for the 1st 15 miles?\r
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Algebra.Com's Answer #347134 by lwsshak3(11628)\"\" \"About 
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After sailing 15 miles a boat changed direction and increased speed by 2 mph. At this 2 mile faster speed an additional 19 miles was traveled. The total travel time was 4 hours. What is the rate of the boat for the 1st 15 miles?
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\n" ); document.write( "let x=rate of speed of boat for 1st 15 miles of travel
\n" ); document.write( "x+2=rate of speed of boat for additional 19 miles of travel
\n" ); document.write( "Travel time=distance/speed
\n" ); document.write( "..
\n" ); document.write( "(15/x)+(19/(x+2))=4
\n" ); document.write( "LCD:x(x+2)
\n" ); document.write( "15(x+2)+19x=4x(x+2)
\n" ); document.write( "15x+30+19x=4x^2+8x
\n" ); document.write( "4x^2-26x-30=0
\n" ); document.write( "2x^2-13x-15=0
\n" ); document.write( "(2x-15)(x+1)
\n" ); document.write( "2x-15=0
\n" ); document.write( "x=15/2=7.5
\n" ); document.write( "or
\n" ); document.write( "x+1=0
\n" ); document.write( "x=-1 (reject, speed>0)
\n" ); document.write( "ans:
\n" ); document.write( "rate of speed of boat for 1st 15 miles of travel=7.5 mph \n" ); document.write( "
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