document.write( "Question 201710: If a race car can go around a track in 5 minutes,then how long will it take to go around the track if it increases its speed by 20%? \n" ); document.write( "

Algebra.Com's Answer #852447 by ikleyn(52965) $\"\"$ $\"About$

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\n" ); document.write( "If a race car can go around a track in 5 minutes, then how long will it take to go around the track
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\n" ); document.write( "\n" ); document.write( "This problem is simple - so, the solution must be simple and short.\r
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document.write( "Let  'd'  be the circumference (the length from start to finish).  It is not given in the problem.\r\n" );
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document.write( "Let  'v'  be the average speed of the car.\r\n" );
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document.write( "We are given that the travel time is 5 minutes.  It means\r\n" );
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document.write( "     = 5 minutes.\r\n" );
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document.write( "Now 'v'  increases by 20%.  The new speed is now 1.2v, and they want you evaluate  .\r\n" );
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document.write( "We write  \r\n" );
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document.write( "     =  = we replace here  by 5 and continue =\r\n" );
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document.write( "             =  = 4.16161616...  minutes  (infinite periodical decimal fraction)\r\n" );
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document.write( "So, the answer is  4.16161616...  minutes.\r\n" );
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document.write( "5 minutes is the same as 5*60 = 300 seconds,  so, in seconds, the new travel time is  \r\n" );
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document.write( "     = 250 seconds, or 4 minutes and 10 seconds.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Thus the problem is solved completely, with explanations accessible to a beginner student.\r
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\n" ); document.write( "\n" ); document.write( "I showed you a formal way to solve, but much shorter than @Theo's explanations in his post.\r
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\n" ); document.write( "\n" ); document.write( "Another way reasoning is THIS:\r
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document.write( "    The speed increased in 1.2 times, the distance remained the same - - - hence, the time decreased in 1.2 times.\r\n" );
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document.write( "    So, the new time is   minutes = 4.16161616... minutes = 4 minutes and 10 seconds.\r\n" );
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\n" ); document.write( "\n" ); document.write( "Thus, you have two ways to build your solution: one way is formal, another way is informal and short.\r
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\n" ); document.write( "\n" ); document.write( "You should understand both ways. They both are elementary.\r
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