document.write( "Question 534356: a runner starts jogging at her house. She jogs 6 miles and then turns around and jogs back to her house. The first part of her job is mostly uphill, so her speed averages 3 miles per hour less than her returning spped. If the total time she spends jogging is 1 3/4 hours, find her speed going and her speed returning \n" ); document.write( "
Algebra.Com's Answer #351490 by ankor@dixie-net.com(22740)\"\" \"About 
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a runner starts jogging at her house. She jogs 6 miles and then turns around and jogs back to her house. The first part of her job is mostly uphill, so her speed averages 3 miles per hour less than her returning speed. If the total time she spends jogging is 1 3/4 hours, find her speed going and her speed returning
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\n" ); document.write( "let s = the uphill speed
\n" ); document.write( "then
\n" ); document.write( "(s+3) = the downhill speed
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\n" ); document.write( "Change time to 1.75 hrs
\n" ); document.write( ":
\n" ); document.write( "Write a time equation, time = dist/speed
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\n" ); document.write( "Up time + down time = total time
\n" ); document.write( "\"6%2Fs\" + \"6%2F%28%28s%2B3%29%29\" = 1.75
\n" ); document.write( "multiply by s(s+3) to clear the denominators, results:
\n" ); document.write( "6(s+3) + 6s = 1.75s(s+3)
\n" ); document.write( "6s + 18 + 6s = 1.75s^2 + 5.25s
\n" ); document.write( "Combine like terms
\n" ); document.write( "0 = 1.75s + 5.25s - 12s - 18
\n" ); document.write( "1.75s - 6.75s - 18 = 0
\n" ); document.write( "Use the quadratic formula to find s
\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"
\n" ); document.write( "x = s; a=1.75, b=-6.75, c=-18
\n" ); document.write( "\"s+=+%28-%286.67%29+%2B-+sqrt%28-6.75%5E2-4%2A1.75%2A-18+%29%29%2F%282%2A-1.75%29+\"
\n" ); document.write( "You can do the rather tedious math here, you should get a positive solution
\n" ); document.write( "s = 5.67 mph, the speed uphill, and obviously, 8.67 mph down
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