backyard is twice

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backyard is twice

by sanju09 » Wed Mar 02, 2011 1:58 am
The length of a rectangular backyard is twice its breadth. A square park of area 600 occupies a third of the total area of the backyard. What is the length of the backyard?
(A) 15
(B) 20
(C) 30
(D) 60
(E) 90


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by BarryLi » Wed Mar 02, 2011 2:06 am
The question states the following:
1) l = 2w
2) 600 = (1/3)lw

Starting with (2),
1800 = lw
1800 = 2w^2
900 = w^2
30 = w
l = 60

The length of the backyard is 60

OA: D

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by Anurag@Gurome » Wed Mar 02, 2011 2:15 am
Let the width of rectangular backyard = w
Then length of rectangular backyard = 2w
Area of rectangular backyard = length * width = 2w^2
600 = (1/3)(2w^2)
900 = w^2
w = 30 implies 2w = 60
So, length of the rectangular backyard = 60

The correct answer is D.
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