<PRE><B>Question 170636</B>
Originally the dimensions of a rectangle were 20 cm by 23 cm. When both dimensions were decreased by the same amount, the area of the rectangle decreased by 120 cm^2. Find the dimensions of the new rectangle.
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Original DATA:
area = 20*23 = 460 cm^2
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New DATA:
area = (20-x)(23-x) cm^2
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EQUATION:
original area - new area = 120 cm^2
460 -[460-43x+x^2] = 120
460 - 460 +43x - x^2 = 120
x^2 - 43x + 120 = 0

x = [43 +- sqrt(43^2 -4*120)}/2

x = [43 +- sqrt(1369)]/2

x = [43 +- 37]/2
Positive solution:

x = 3 cm or x = 40 cm
Only x = 3 cm is realistic.
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Cheers,
Stan H.</PRE>