<PRE><B>Question 1166545</B>
&lt;br&gt;
This is an example of a problem that is solved far more easily informally than with formal algebra.  So I will explain what I would do if I were working this problem and a formal algebraic solution was required.&lt;br&gt;
82% done means 18% remains; 18% of 200*25 feet is 900 square feet.  If the width of the strip is x, then&lt;br&gt;
{{{(200-2x)(25-2x) = 900}}}
{{{5000-450x+4x^2 = 900}}}
{{{4x^2-450x+4100 = 0}}}
{{{2x^2-225x+2050 = 0}}}&lt;br&gt;
UGH! That looks REALLY nasty....&lt;br&gt;
Instead of trying to factor that, I would stop at this point and solve the problem with logical reasoning and some simple mental arithmetic; then come back to my formal algebraic solution.&lt;br&gt;
width 5 --&gt; 190*15 = 2850
width 10 --&gt; 180*5 = 900&lt;br&gt;
AHA! the answer is 10.&lt;br&gt;
So now back to the formal algebra.&lt;br&gt;
{{{(x-10)(2x-205) = 0}}}&lt;br&gt;
The second possible solution is rejected, since it makes no sense in the original problem.&lt;br&gt;
ANSWER: The strip is 10 feet wide.&lt;br&gt;
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