SOLUTION: Construction. A garden area is 30 ft long and 20 ft wide. a path of uniform width is set around the edge. If the remaining garden area is 400 ft^2 , what is the width of the path?

Algebra ->  Customizable Word Problem Solvers  -> Geometry -> SOLUTION: Construction. A garden area is 30 ft long and 20 ft wide. a path of uniform width is set around the edge. If the remaining garden area is 400 ft^2 , what is the width of the path?       Log On

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Question 119472: Construction. A garden area is 30 ft long and 20 ft wide. a path of uniform width is set around the edge. If the remaining garden area is 400 ft^2 , what is the width of the path?
So if I squared 20, 30, 400 And I get something like 30 ft, would I be terribly wrong?

Answer by ptaylor(2198) About Me  (Show Source):
You can put this solution on YOUR website!
I THINK YOU BEST APPROACH ON WORD PROBLEMS IS TO LAY THEM OUT IN AN ORDERLY FASHION IDENTIFYING WHAT NEEDS TO BE DETERMINED AS YOU GO. I HAVE TRIED TO DO THIS BELOW:
Area(A)=Length(l) times Width(w) or A=l*w
Let w=the uniform width of the path. Note that the path is inside the original garden

Note: draw the garden and path and the statement below will be obvious.
Area of garden after path is put in= (20-2w)*(30-2w) =600-100w+4w^2 and this we are told equals 400 ft^2. So:
600-100w+4w^2=400 subtract 400 from both sides
600-400-100w+4w^2=400-400 collect like terms
4w^2-100w+200=0 divide each term by 4
w^2-25w+50=0 quadratic in standard form. Solve using the quadratic formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%2825+%2B-+sqrt%28-25%5E2-4%2A1%2A50+%29%29%2F%282%2A1%29+
x+=+%2825+%2B-+sqrt%28+625-200+%29%29%2F%282%29+
x+=+%2825+%2B-+sqrt%28+425%29%29%2F%282%29+
x+=+%2825+%2B-+20.6%29%2F%282%29+
x+=+%2825+%2B+20.6%29%2F%282%29+
x+=+%2845.6%29%2F%282%29+
x=22.8 ft----------------------too large-- gives a negative value for length and width--- not a correct answer
and
x+=+%2825+-+20.6%29%2F%282%29+
x+=+%284.4%29%2F%282%29+
x=2.2 ft----ans
(30-2*2.2)(20-2*2.2)=400
(30-4.4)(20-4.4)=400
25.6*15.6=400
~~~400=400
Hope this helps---ptaylor