document.write( "Question 1206933: The barges traveled downstream at 12 mph and upstream at 7 mph. What was their downstream travel time if it was 10 hours less than the time required to travel the same distance upstream? \n" ); document.write( "

Algebra.Com's Answer #844660 by ikleyn(52908) $\"\"$ $\"About$

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\n" ); document.write( "The barges traveled downstream at 12 mph and upstream at 7 mph.
\n" ); document.write( "What was their downstream travel time if it was 10 hours less
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document.write( "It is easy.\r\n" );
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document.write( "Let t be the downstream travel time, in hours.\r\n" );
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document.write( "Then the upstream travel time is (t+10) hours, according to the problem.\r\n" );
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document.write( "The travel distance downstream is 12t      miles (the rate times time);\r\n" );
document.write( "The travel distance   upstream is  7(t+10) miles (the rate times time).\r\n" );
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document.write( "So, we write this equation\r\n" );
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document.write( "    12t = 7*(t+10)\r\n" );
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document.write( "saying that the travel distance is the same in both directions.\r\n" );
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document.write( "Simplify and find t\r\n" );
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document.write( "    12t = 7t + 70\r\n" );
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document.write( "    12t - 7t = 70\r\n" );
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document.write( "        5t   = 70\r\n" );
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document.write( "         t   = 70/5 = 14.\r\n" );
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document.write( "ANSWER.  The downstream travel time is 14 hours.\r\n" );
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