document.write( "Question 570740: Helena drives from town A to town B at x mph, and drives back at y mph. What is her average speed for the round trip? If the round trip takes t hours, how far apart are the towns? \n" ); document.write( "

Algebra.Com's Answer #367748 by josmiceli(19441) $\"\"$ $\"About$

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Average speed is always ( total distance traveled ) / ( total time it takes )
\n" ); document.write( "I will say that the towns are $\"+d+\"$ miles apart
\n" ); document.write( "----------
\n" ); document.write( "Time going from A to B:
\n" ); document.write( " $\"+d%2Fx+\"$
\n" ); document.write( "Time going from B to A:
\n" ); document.write( " $\"+d%2Fy+\"$
\n" ); document.write( "----------
\n" ); document.write( "Ave speed = $\"+%282d%29+%2F+%28+d%2Fx+%2B+d%2Fy+%29+\"$
\n" ); document.write( "Divide top and bottom by $\"d\"$
\n" ); document.write( "Ave speed = $\"+2+%2F+%28+1%2Fx+%2B+1%2Fy+%29+\"$
\n" ); document.write( "Multiply top and bottom by $\"+x%2Ay+\"$
\n" ); document.write( "Ave speed = $\"+%282%2Ax%2Ay%29+%2F+%28+x+%2B+y+%29+\"$
\n" ); document.write( "---------------
\n" ); document.write( "If the round trip takes $\"+t+\"$ hrs,
\n" ); document.write( " $\"+%282d%29%2Ft+=+%282%2Ax%2Ay%29+%2F+%28+x+%2B+y+%29+\"$
\n" ); document.write( "Distance apart is $\"+d+=+%28x%2Ay%2At%29+%2F+%28+x+%2B+y+%29+\"$ \n" ); document.write( "

\n" );