document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1173839>Question 1173839</A>: <I><SPAN STYLE=\"word-break: break-all;\"> After sailing 13 mi, a sailor changed direction and increased the boat's speed by 4 mph. An additional 17 mi was sailed at the increased speed. The total sailing time was 2 h. Find the rate of the boat for the first 13 mi. </SPAN>\n" );
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document.write( "Let the speed for the first part be x; then the speed for the second part is x+4.<br><BR>\n" );
document.write( "The time for each part is the distance, divided by the speed; the total time is 2 hours:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=13%2Fx+%2B+17%2F%28x%2B4%29+=+2 ALIGN=MIDDLE  ALT=\"13%2Fx+%2B+17%2F%28x%2B4%29+=+2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "That equation is solved relatively easily with basic algebra.<br><BR>\n" );
document.write( "However, if you take a moment to look at the numbers in the equation, you might be able to see almost immediately that x=13 works....<br><BR>\n" );
document.write( "ANSWER: 13mph for the first 13 miles.<br><BR>\n" );
document.write( "CHECK: 13/13 + 17/(13+4) = 1+1 = 2<br><BR>\n" );
document.write( " </SPAN>\n" );
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