document.write( "Question 838510: It took Gina 3.6 hours to drive to her mother's house on thursday morning.On her return trip on friday night, traffic was heavier,so it took her 4 hours.Her average speed on friday was 4 mph slower than on thursday. What was her average speed on friday ? \n" ); document.write( "

Algebra.Com's Answer #505140 by josgarithmetic(39614) $\"\"$ $\"About$

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The distance is the same both ways, both days.\r
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\n" ); document.write( "\n" ); document.write( "_____________speed_________time__________distance
\n" ); document.write( "Thursday_____r_____________3.6___________d
\n" ); document.write( "Friday_______r-4___________4_____________d\r
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\n" ); document.write( "\n" ); document.write( "That's one way to arrange the data. The question is, \"speed on friday\". We can reassign the rate variable like this:\r
\n" ); document.write( "\n" ); document.write( "_____________speed_________time__________distance
\n" ); document.write( "Thursday_____r+4___________3.6___________d
\n" ); document.write( "Friday________r____________4_____________d\r
\n" ); document.write( "\n" ); document.write( "The rate on Friday is still 4 mph slower than thursday, so this data arrangement should still work.\r
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\n" ); document.write( "\n" ); document.write( "RT=D, typical meanings, so we should understand adding this information:\r
\n" ); document.write( "\n" ); document.write( "_____________speed_________time__________distance
\n" ); document.write( "Thursday_____r+4___________3.6___________d=(r+4)(3.6)
\n" ); document.write( "Friday________r____________4_____________d=r*4\r
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\n" ); document.write( "\n" ); document.write( "All needed is to solve for r in $\"%28r%2B4%29%283.6%29=r%2A4\"$ , rewritten as $\"highlight%28%283.6%29%28r%2B4%29=4r%29\"$ \n" ); document.write( "

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