document.write( "Question 887211: Tina is training for a biathlon. To train for the running portion of the race, she runs 10 miles each day, over the same course. The first 4 miles of the course is on level ground, while the last 6 miles is downhill. She runs 4 miles per hour slower on level ground than she runs downhill. If the complete course takes 1 hour, how fast does she run on the downhill part of the course? \n" ); document.write( "
Algebra.Com's Answer #536450 by lwsshak3(11628)\"\" \"About 
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Tina is training for a biathlon. To train for the running portion of the race, she runs 10 miles each day, over the same course. The first 4 miles of the course is on level ground, while the last 6 miles is downhill. She runs 4 miles per hour slower on level ground than she runs downhill. If the complete course takes 1 hour, how fast does she run on the downhill part of the course?
\n" ); document.write( "***
\n" ); document.write( "let x=speed Tina runs downhill
\n" ); document.write( "x-4=speed Tina runs on level ground
\n" ); document.write( "travel time=distance/speed
\n" ); document.write( "\"6%2Fx%2B4%2F%28x-4%29=1\"
\n" ); document.write( "lcd:x(x-4)
\n" ); document.write( "6x-24+4x=x^2-4x
\n" ); document.write( "x^2-14x+24=0
\n" ); document.write( "(x-12)(x-2)=0
\n" ); document.write( "x=2 (reject)
\n" ); document.write( "or
\n" ); document.write( "x=12
\n" ); document.write( "x-4=8
\n" ); document.write( "speed Tina runs downhill=12 mph
\n" ); document.write( "speed Tina runs on level ground=8 mph \n" ); document.write( "
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