Algebra.Com's Answer #665156 by ikleyn(52778)![\"\"](\"/images/stars/stars-13.gif\")  
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document.write( "Pratap Puri rowed 14 miles down a river in 2 hours, but the return trip took him 3 1/2 one half hours.
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document.write( "Find the rate Pratap can row in still water and find the rate of the current
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document.write( "2 hours = 2 hours;   hours =  hours.\r\n" );
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document.write( "The standard way of solving such problem is this. \r\n" );
document.write( "From the condition you have these two equations\r\n" );
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document.write( " = u + v, (1)\r\n" );
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document.write( " = u - v. (2)\r\n" );
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document.write( "The left side of the equation (1) is the speed of the boat relative the bank of the river when rowing with the current, \r\n" );
document.write( "and it is the sum of the rate of the boat in still water and the current rate.\r\n" );
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document.write( "The left side of the equation (2) is the speed of the boat relative the bank of the river when rowing against the current, \r\n" );
document.write( "and it is the difference of the rate of the boat in still water and the current rate.\r\n" );
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document.write( "Simplify the equations (1) and (2):\r\n" );
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document.write( "u + v = 7, (3)\r\n" );
document.write( "u - v = 4. (4)\r\n" );
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document.write( "Now add the equations (3) and (4). You will get\r\n" );
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document.write( "2u = 7 + 4 = 11, or u =  = 5.5.\r\n" );
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document.write( "Thus you just found the speed of the boat in still water. It is 5.5 miles per hour.\r\n" );
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document.write( "Now it is easy to find the speed of current. It is\r\n" );
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document.write( "v = 7 - u = 7 - 5.5 = 1.5 miles per hour.\r\n" );
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document.write( "Check. The boat' speed with the current is 5.5 + 1.5 = 7 mph.\r\n" );
document.write( " The time for down a river trip is  = 2 hours.\r\n" );
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document.write( " The boat' speed against the current is 5.5 - 1.5 = 4 mph.\r\n" );
document.write( " The time for the return trip is  = hours.\r\n" );
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document.write( " The solution was checked and found to be correct.\r\n" );
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document.write( "Answer. The speed of the boat in still water is 5.5 mph. The speed of current is 1.5 mph.\r\n" );
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document.write( "Solved.\r
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document.write( "It is a typical Upstream and Downstream round trips word problem.\r
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document.write( "You can find similar fully solved similar problems on upstream and downstream round trips with detailed solutions in the lessons \r
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document.write( " - Wind and Current problems \r
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document.write( " - More problems on upstream and downstream round trips \r
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document.write( " - Selected problems from the archive on the boat floating Upstream and Downstream \r
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document.write( "Read them attentively and learn how to solve this type of problems once and for all.\r
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document.write( "Also, you have this free of charge online textbook in ALGEBRA-I in this site\r
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document.write( " - ALGEBRA-I - YOUR ONLINE TEXTBOOK.\r
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document.write( "The referred lessons are the part of this textbook under the topic \"Travel and Distance problems\" of the section \"Word problems\" .\r
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