document.write( "Question 654156: car A and car B enter an expressway at the same time and same place and head the same direction. car A travels at 70 miles per hour. If after 2.5 hours car B is 50 miles behind car A what is the speed of car B \n" ); document.write( "

Algebra.Com's Answer #408634 by Edwin McCravy(20060) $\"\"$ $\"About$

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car A and car B enter an expressway at the same time and same place and head the same direction. car A travels at 70 miles per hour. If after 2.5 hours car B is 50 miles behind car A what is the speed of car B.
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document.write( "How to do it in your head:\r\n" );
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document.write( "They've separated 50 miles in 2.5 hours so they would separate\r\n" );
document.write( "100 miles in 5 hours or 20 miles in 1 hour. So car B was going \r\n" );
document.write( "20 mph slower or 50 mph.\r\n" );
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document.write( "How to do it by algebra:\r\n" );
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document.write( "         rate  ×  time  =  distance    \r\n" );
document.write( "car A     70       2.5       175 \r\n" );
document.write( "car B      x       2.5       2.5x\r\n" );
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document.write( "             The equation comes from:\r\n" );
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document.write( "                             =  - 50\r\n" );
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document.write( "                                2.5x = 175 - 50\r\n" );
document.write( "                                2.5x = 125\r\n" );
document.write( "                                   x = 50 mph     \r\n" );
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document.write( "Edwin

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