document.write( "Question 675087: two friends go running. Leaving from the same point, 1 heads south at 7 mph for 3 hours and then heads east at 5 mph for 1 hour. The other friend heads west for two hours at 6 mph and then heads north at 5 mph for 2 hours. Which of the following expresses the distance, in miles, between the two friends after 4 hours? \n" ); document.write( "
Algebra.Com's Answer #419546 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "We will use the notation: \r\n" );
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document.write( "North = UP, South = DOWN, East = RIGHT, West = LEFT\r\n" );
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document.write( "We will indicate the first runner's path with green arrows,\r\n" );
document.write( "starting at point P:\r\n" );
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document.write( ">>One heads south at 7 mph for 3 hours...<< \r\n" );
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document.write( "So he or she goes 7×3 or 21 miles DOWNWARD from point P,\r\n" );
document.write( "like this:\r\n" );
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document.write( ">>and then heads east at 5 mph for 1 hour.<<\r\n" );
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document.write( "So he or she turns and goes 5×1 or 5 miles TO THE RIGHT,\r\n" );
document.write( "like this:\r\n" );
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document.write( ">> The other friend heads west for two hours at 6 mph <<\r\n" );
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document.write( "So he or she goes 2×6 or 12 miles LEFT from point P.\r\n" );
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document.write( "We will indicate the other runner's path with red arrows,\r\n" );
document.write( "starting a point P, like this:\r\n" );
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document.write( ">>and then heads north at 5 mph for 2 hours.<<\r\n" );
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document.write( "So he or she turns and goes 5×2 or 10 miles UP,\r\n" );
document.write( "like this: \r\n" );
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document.write( "So at the end of 4 hours the first runner is at the end of\r\n" );
document.write( "the green path and the other runner is at the end of the red path.\r\n" );
document.write( "We want to know how far they are apart, so let's draw a blue line\r\n" );
document.write( "between where the runners are after 4 hours:\r\n" );
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document.write( "Now we'll draw a horizontal and vertical black line so that the\r\n" );
document.write( "blue line will be the hypotenuse of a big right triangle, like this:\r\n" );
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document.write( "We'll draw two points on the black lines directly\r\n" );
document.write( "above and directly to the right of point P, like this:\r\n" );
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document.write( "Now we can see that the upper horizontal side of the big\r\n" );
document.write( "right triangle is 12+5 or 17 miles and the vertical side\r\n" );
document.write( "of the big right triangle is 10+21 or 31 miles.  Therefore\r\n" );
document.write( "we can use the Pythagorean theoren and find the distance\r\n" );
document.write( "between the runners (the blue line), which is the hypotenuse\r\n" );
document.write( "of the big right triangle:\r\n" );
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document.write( "(distance between runners)² = 17² + 31²\r\n" );
document.write( "(distance between runners)² = 289 + 961\r\n" );
document.write( "(distance between runners)² = 1250\r\n" );
document.write( "   distance between runners = √1250\r\n" );
document.write( "   distance between runners = √625·2\r\n" );
document.write( "   distance between runners = 25√2\r\n" );
document.write( "   distance between runners is approximately 35.35533906 miles, which\r\n" );
document.write( "you should round off as your teacher desires, perhaps to 35.4 miles.\r\n" );
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document.write( "Edwin
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