document.write( "Question 407195: joshua drove 200 miles to visit his grandmother. because of the rainy weather, his average speed wa 10 mph less than his average speed going to his grandmother's home. if the return trip took 1 hour longer, how fast did he drive on his return trip? \n" ); document.write( "

Algebra.Com's Answer #287061 by robertb(5830) $\"\"$ $\"About$

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Let r = rate in the return trip
\n" ); document.write( "==> rate in going to grandmother = r + 10
\n" ); document.write( "==> $\"200%2Fr++-+200%2F%28r+%2B+10%29+=+1\"$ , using the formula t = d/r.
\n" ); document.write( "==> $\"%28200r+%2B+2000+-+200r%29%2F%28r%28r%2B10%29%29+=+1\"$
\n" ); document.write( "==> $\"2000+=+r%28r%2B10%29+=+r%5E2+%2B+10r\"$
\n" ); document.write( "<==> $\"r%5E2+%2B+10r++-+2000+=+0\"$
\n" ); document.write( "<==> (r + 50)(r - 40) = 0
\n" ); document.write( "==> r = 40 miles per hour, the rate in the return trip. \n" ); document.write( "

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