Question 351137
The width of a rectangle is 20 cm more than half the length.
Its area is 4800 sq.cm.
Find its width.
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Let the length be "2x".
Then the width is "x+20".
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Area = length * width
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4800 = (2x)(x+20)
4800 = 2x^2+40x
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Rearrange to get:
2x^2+40x-4800 = 0
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Divide thru by 2 to get:
x^2 + 20x - 2400 = 0
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Factor to get:
(x-40)(x+60) = 0
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Positive solution:
x = 40
width = x+20 = 40+20 = 60 ft.
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Comment:  That is a pretty tough problem
for a 4th grader.  Your cousin must be at
an advanced level in math.  Congratulations.
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Cheers,
Stan H.