document.write( "Question 1182496: Mang Lino is planning to construct a rectangular coop with the width 2 meter shorter that thrice the length. He wants to use at least 4 meters of chicken wire but at most 20 meters of the material. What are the possible integral dimensions of the coop? What is the inequality statement? \n" ); document.write( "
Algebra.Com's Answer #812557 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "W = width
\n" ); document.write( "L = length
\n" ); document.write( "which are some positive whole numbers. The units for each are in meters.\r
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\n" ); document.write( "\n" ); document.write( "The width is 2 meters shorter than thrice the length, meaning
\n" ); document.write( "W = 3L-2
\n" ); document.write( "since 3L is thrice, or three times, the length. Then we subtract off 2 from that result to get the width W.\r
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\n" ); document.write( "\n" ); document.write( "The perimeter of the rectangle with length L and width W is
\n" ); document.write( "P = 2L+2W
\n" ); document.write( "we add up two copies of L and W each to get the total distance around the rectangle. This is the amount of fencing needed for the rectangular coop.\r
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\n" ); document.write( "\n" ); document.write( "He wants to use at least 4 meters but at most 20 meters
\n" ); document.write( "This places boundaries on how low and how high P can get
\n" ); document.write( "P = 4 is the smallest possible perimeter
\n" ); document.write( "P = 20 is the largest possible perimeter
\n" ); document.write( "That leads us to \"4+%3C=+P+%3C=+20\"\r
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\n" ); document.write( "\n" ); document.write( "Let's replace P with 2L+2W to get
\n" ); document.write( "\"4+%3C=+P+%3C=+20\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"4+%3C=+2L%2B2W+%3C=+20\"\r
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\n" ); document.write( "\n" ); document.write( "\"4+%3C=+2%28L%2BW%29+%3C=+20\"\r
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\n" ); document.write( "\n" ); document.write( "\"2+%3C=+L%2BW+%3C=+10\"
\n" ); document.write( "In the last step, I divided everything by 2\r
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\n" ); document.write( "\n" ); document.write( "Now let's replace W with 3L-2 and isolate L like so
\n" ); document.write( "\"2+%3C=+L%2BW+%3C=+10\"\r
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\n" ); document.write( "\n" ); document.write( "\"2+%3C=+L%2B3L-2+%3C=+10\"\r
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\n" ); document.write( "\n" ); document.write( "\"2+%3C=+4L-2+%3C=+10\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%2B2+%3C=+4L-2%2B2+%3C=+10%2B2\" Adding 2 to all sides\r
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\n" ); document.write( "\n" ); document.write( "\"4+%3C=+4L+%3C=+12\"\r
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\n" ); document.write( "\n" ); document.write( "\"4%2F4+%3C=+4L%2F4+%3C=+12%2F4\" Dividing all sides by 4\r
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\n" ); document.write( "\n" ); document.write( "\"1+%3C=+L+%3C=+3\"\r
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\n" ); document.write( "\n" ); document.write( "This tells us that L = 1 is the smallest length possible while L = 3 is the largest length possible. L = 2 is also possible as it's right in between. These are the only integer lengths possible that meet the required conditions.\r
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\n" ); document.write( "\n" ); document.write( "If L = 1, then
\n" ); document.write( "W = 3L-2
\n" ); document.write( "W = 3(1)-2
\n" ); document.write( "W = 1
\n" ); document.write( "So L = 1 leads to W = 1
\n" ); document.write( "The perimeter would be P = 2L+2W = 2(1)+2(1) = 4
\n" ); document.write( "So this is the case where he uses the least amount of wire possible (4 meters of it).\r
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\n" ); document.write( "\n" ); document.write( "If L = 2, then,
\n" ); document.write( "W = 3L-2
\n" ); document.write( "W = 3(2)-2
\n" ); document.write( "W = 4
\n" ); document.write( "So L = 2 leads to W = 4
\n" ); document.write( "The perimeter would be P = 2L+2W = 2(2)+2(4) = 12
\n" ); document.write( "He is now using 12 meters of wire. This fits the inequality \"4+%3C=+P+%3C=+20\" because \"4+%3C=+12+%3C=+20\" is a true statement.\r
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\n" ); document.write( "\n" ); document.write( "Lastly, if L = 3, then
\n" ); document.write( "W = 3L-2
\n" ); document.write( "W = 3(3)-2
\n" ); document.write( "W = 7
\n" ); document.write( "So L = 3 leads to W = 7
\n" ); document.write( "The perimeter would be P = 2L+2W = 2(3)+2(7) = 20
\n" ); document.write( "Telling us that he's using the most wire he's alloting or budgeting out. \r
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\n" ); document.write( "\n" ); document.write( "To recap everything:
  • The 1 m by 1 m coop needs 4 m of wire
  • The 2 m by 4 m coop needs 12 m of wire
  • The 3 m by 7 m coop needs 20 m of wire
These are the only three possible cases if we want integral (ie integer) dimensions to the rectangle.
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