document.write( "Question 311840: Robot A takes 6 minutes to weld a frame. With the help of Robot B, the job can be done in 4 minutes. How long would it take Robot B working alone? \n" ); document.write( "
Algebra.Com's Answer #222975 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
Robot A takes 6 minutes to weld a frame. With the help of Robot B, the job can be done in 4 minutes. How long would it take Robot B working alone?
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document.write( "Make this chart\r\n" );
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document.write( "                Number of frames welded | time | rate in frames/minute\r\n" );
document.write( "Robot A alone                           |      | \r\n" );
document.write( "Robot B alone                           |      |\r\n" );
document.write( "----------------------------------------------------------------------\r\n" );
document.write( "Both together                           |      |\r\n" );
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document.write( "The question asks:\r\n" );
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\n" ); document.write( ">>...How long would it take Robot B working alone?...<<
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document.write( "Let the answer to that be x.  It would take Robot B x minutes alone to\r\n" );
document.write( "weld 1 frame.  So fill in 1 for the numer of frames Robot A alone could \r\n" );
document.write( "weld and x for the time:\r\n" );
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document.write( "                Number of frames welded | time | rate in frames/minute\r\n" );
document.write( "Robot A alone                           |      | \r\n" );
document.write( "Robot B alone             1             |   x  |\r\n" );
document.write( "----------------------------------------------------------------------\r\n" );
document.write( "Both together                           |      |\r\n" );
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document.write( "

\n" ); document.write( ">>...Robot A takes 6 minutes to weld a frame...<<
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document.write( "Since robot A takes 6 minute to weld 1 frame, fill in\r\n" );
document.write( "1 for the number of frames and 6 for the time for Robot A\r\n" );
document.write( "alone:\r\n" );
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document.write( "                Number of frames welded | time | rate in frames/minute\r\n" );
document.write( "Robot A alone             1             |   6  | \r\n" );
document.write( "Robot B alone             1             |   x  |\r\n" );
document.write( "----------------------------------------------------------------------\r\n" );
document.write( "Both together                           |      |\r\n" );
document.write( "

\n" ); document.write( ">>...With the help of Robot B, the job can be done in 4 minutes...<<
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document.write( "Since it takes 4 minute for both together to weld 1 frame, fill in\r\n" );
document.write( "1 for the number of frames and 4 for the time for both together:\r\n" );
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document.write( "                Number of frames welded | time | rate in frames/minute\r\n" );
document.write( "Robot A alone             1             |   6  | \r\n" );
document.write( "Robot B alone             1             |   x  |\r\n" );
document.write( "----------------------------------------------------------------------\r\n" );
document.write( "Both together             1             |   4  |\r\n" );
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document.write( "Now finish filling in the chart by calculating the three rates in\r\n" );
document.write( "frames per minute by dividing the number of frames by the number\r\n" );
document.write( "of minutes:\r\n" );
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document.write( "                Number of frames welded | time | rate in frames/minute\r\n" );
document.write( "Robot A alone             1             |   6  |         1/6 \r\n" );
document.write( "Robot B alone             1             |   x  |         1/x\r\n" );
document.write( "----------------------------------------------------------------------\r\n" );
document.write( "Both together             1             |   4  |         1/4\r\n" );
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document.write( "Now we make the equation by this:\r\n" );
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document.write( "     Robot A's rate alone + Robot B's rate alone = their rate together:\r\n" );
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document.write( "                1/6       +           1/x        =        1/4\r\n" );
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document.write( "\"1%2F6+%2B+1%2Fx+=+1%2F4\"\r\n" );
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document.write( "Multiply thru by 12x\r\n" );
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document.write( "\"2x+%2B+12+=+3x\"\r\n" );
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document.write( "\"12=x\"\r\n" );
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document.write( "It would take Robot B 12 minutes to weld one frame.\r\n" );
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document.write( "Edwin
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