document.write( "Question 1205404: The telephone poles along a road are 20m apart and a car travels from the first to the fifteenth in 10½ seconds. Calculate the speed of the car in km/h. \n" ); document.write( "

Algebra.Com's Answer #842169 by ikleyn(52788) $\"\"$ $\"About$

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\n" ); document.write( "The telephone poles along a road are 20m apart and a car travels from the first
\n" ); document.write( "to the fifteenth in 10½ seconds. Calculate the speed of the car in km/h.
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document.write( "From the first to the 15-th telephone pole, there are 15-1 = 14 intervals ( ! not 15 ! ).\r\n" );
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document.write( "Therefore, the distance from the first to the 15-th telephone pole is  20*14 = 280 meters  ( ! not 300 meters ! ).\r\n" );
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document.write( "The speed of the car is the distance divided by the time\r\n" );
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document.write( "    speed =  = 26 m/s.\r\n" );
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document.write( "In kilometers per hour, this speed is\r\n" );
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document.write( "     = 96 km/h.\r\n" );
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document.write( "ANSWER.  The speed of the car is 96 km/h.\r\n" );
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\n" ); document.write( "\n" ); document.write( "The lesson to learn from my post is that if n points are uniformly/equidistantly
\n" ); document.write( "placed on a straight line, then there are (n-1) equal intervals between them.\r
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\n" ); document.write( "\n" ); document.write( "This problem is specially designed/intended to teach students to this wisdom.\r
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