document.write( "Question 1144181: Suppose that the height (in centimeters) of a candle is a linear function of the amount of time (in hours) it has been burning. After 8\r
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Algebra.Com's Answer #765206 by ikleyn(52781) $\"\"$ $\"About$

You can put this solution on YOUR website!
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document.write( "In 12 hours of burning, from 8 hours to 20 hours, the height of the candle decreases by 28.4 - 26 = 2.4 cm.\r\n" );
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document.write( "Thus the height decreases  = 0.2 cm per hour.\r\n" );
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document.write( "11 hours after burning start, the height of the candle was (! 3 hours after 8 hours mark !)  28.4 - 0.2*3 = 27.8 cm.\r\n" );
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document.write( "ANSWER.  The height of the candle after 11 hours of burning is/was 27.8 cm.\r\n" );
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\n" ); document.write( "\n" ); document.write( "If you want to see many other similar solved problems, look into the lesson\r
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\n" ); document.write( "\n" ); document.write( "Such problems are always easier to solve via their physical meaning than using formal formulas.\r
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\n" ); document.write( "\n" ); document.write( "It is also much more promising/perspective/solid educational strategy.\r
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\n" ); document.write( "\n" ); document.write( "First, the students may start earlier solving such problems: at their 5-th or 6-th grades level,
\n" ); document.write( "instead of 7-th or 8-th grade with formal formulas.\r
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\n" ); document.write( "\n" ); document.write( "Second, the students may develop, apply and use their physical intuition and their common sense.\r
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\n" ); document.write( "\n" ); document.write( "Third, it is the way to exercise their mind and make it more flexible (and more powerful !)\r
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\n" ); document.write( "\n" ); document.write( "It is why I ALWAYS prefer using a meaningful context against a formal approach while solving such problems.\r
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\n" ); document.write( "\n" ); document.write( "And only when the students at their 5-th and 6-th grades will learn on how to solve such problems based on their meaningful context,\r
\n" ); document.write( "\n" ); document.write( "the time will come, when they can learn it on the next level via using formal formulas - but then they will not come \r
\n" ); document.write( "\n" ); document.write( "to this forum for our help -- they will be able to do it on their own (!) -- which is a dream of any tutor/teacher.\r
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\n" ); document.write( "\n" ); document.write( " One more time, let me repeat my major idea, again:\r
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document.write( "For such problems, the subject of teaching is to teach students solve the problems at the meaningful level.\r\n" );
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document.write( "At the formal formulas level, there is NO subject to teach, at all : it is entirely mechanical work.\r\n" );
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document.write( "It is just not about solving meaningful problems: it is entirely about using linear interpolation or extrapolation formulas.\r\n" );
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