document.write( "Question 1207855: 1. A wooden access ramp is being built to reach a platform that sits 30 inches above the floor. The ramp drops 2 inches for every 25-inch run.
\n" ); document.write( "Write a linear equation that relates the height y of the ramp above the floor to the horizontal distance x from the platform.\r
\n" ); document.write( "\n" ); document.write( "2. A report in the Child Trends DataBase indicated that, in 1996, 22.2% of twelfth grade students reported daily use of cigarettes. In 2006, 12.2% of twelfth grade students reported daily use of cigarettes. Write a linear equation that relates the percent y of twelfth grade students who smoke cigarettes daily to the number x of years after 1996. \n" ); document.write( "

Algebra.Com's Answer #845986 by ikleyn(52781) $\"\"$ $\"About$

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\n" ); document.write( "1. A wooden access ramp is being built to reach a platform that sits 30 inches above the floor.
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\n" ); document.write( "Write a linear equation that relates the height y of the ramp above the floor
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\n" ); document.write( "\n" ); document.write( " In this my post, I will solve part/question/problem 1, ONLY.\r
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\n" ); document.write( "\n" ); document.write( " For explanations, see my notes after the solution.\r
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document.write( "The linear equation for this case is of the form y = ax + b.\r\n" );
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document.write( "Here \"a\" is the slope, which is the ratio of the rise in y to the run in x.\r\n" );
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document.write( "Notice that according to the problem's question, x is the distance from the platform.\r\n" );
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document.write( "So, physically, y = 30 inches at x = 0, and y decreases gradually to 0 (zero), as \r\n" );
document.write( "coordinate x goes from the platform.  Thus, in this case the slope in the equation is NEGATIVE.\r\n" );
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document.write( "Next, the problem says that ramp drops 2 inches for every 25 inch run.\r\n" );
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document.write( "It gives us the info to calculate the slope  a =  =  = -0.08.\r\n" );
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document.write( "So, our equation has the form  \r\n" );
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document.write( "    y = -0.08x + b.    (1)\r\n" );
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document.write( "To find \"b\", use the fact that at x= 0 the height is 30 inches, where the platform is sits.\r\n" );
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document.write( "So, in equation (1) put x= 0 and y= 30.  You will get\r\n" );
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document.write( "    0 = -0.08*0 + b,\r\n" );
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document.write( "or\r\n" );
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document.write( "    30 = 0 + b,\r\n" );
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document.write( "     b = 30.\r\n" );
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document.write( "So, your final equation is  y = -0.08*x + 30, y in inches, x in inches.    ANSWER\r\n" );
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\n" ); document.write( "\n" ); document.write( "At this point, the problem is solved in full and all necessary explanations are provided.\r
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\n" ); document.write( "\n" ); document.write( "Notice that I could write the final equation in one line, omitting all explanations.\r
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\n" ); document.write( "\n" ); document.write( "It would be enough for a knowledgeable student (had he come with this question).\r
\n" ); document.write( "\n" ); document.write( "But I wrote explaining all details for a person who learns slowly and knows almost nothing in the subject.\r
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