Question 71023
A rectangular garden is to be surrounded by a walkway of constant width.  The garden's dimensions are 30 ft by 40 ft.  The total area, garden plus walkway, is to be 1800 ft2.  What must be the width of the walkway to the nearest 
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Draw the picture.
Let the width of the walkway be "w" ft.
Then the width of the garden plus walkway is "30+2x"
and the length of the garden plus walkway is "40+2x"
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EQUATION:
(30+2x)(40+2x) = 1800 sq ft.
4(15+x)(20+x) = 1800
x^2+35x+300=450
x^2+35x-150=0
Use quadratic formula to get:
x=[-35+sqrt(35^2-4*-150)]/2
x=[-35+-sqrt1825]/2
x=[-35+-42.72]/2
x=7.72/2
x=3.86 ft
Cheers,
Stan H.