document.write( "Question 607449: A jogger ran 9 miles in an hour. For the last 4 miles he jogged 2 mph slower than he did for the first 5 miles. How fast did he jog for the first 5 miles? \n" ); document.write( "

Algebra.Com's Answer #382897 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

You can put this solution on YOUR website!
I misunderstood this problem, sorry!
\n" ); document.write( "let s = his speed the first 5 mi
\n" ); document.write( "then
\n" ); document.write( "(s-2) = his speed the last 4 mi
\n" ); document.write( ":
\n" ); document.write( "Write a time equation; time = dist/speed
\n" ); document.write( ":
\n" ); document.write( " $\"5%2Fs\"$ + $\"4%2F%28%28s-2%29%29\"$ = 1
\n" ); document.write( "multiply by s(s-2), results
\n" ); document.write( "5(s-2) + 4s = s(s-2)
\n" ); document.write( ":
\n" ); document.write( "5s - 10 + 4s = s^2 - 2s
\n" ); document.write( "9s - 10 = s^2 - 2s
\n" ); document.write( "0 = s^2 - 2s - 9s + 10
\n" ); document.write( "A quadratic equation
\n" ); document.write( "s^2 - 11s + 10 = 0
\n" ); document.write( "Factors to
\n" ); document.write( "(s-1)(s-10) = 0
\n" ); document.write( "two solutions
\n" ); document.write( "s = 1
\n" ); document.write( "and
\n" ); document.write( "s = 10 mph is the only reasonable answer for the first 5 miles
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "See if this checks out, find the times
\n" ); document.write( "5/10 + 4/8 = 1 \n" ); document.write( "

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