<PRE><B>Question 1138605</B>
A rectangular sheet of tin is 15cm long and 9cm wide. A uniform strip is to be cut off around the sheet. The examining area is 112cm squared. Calculate the width of the strip. The answer is 0.5 cm. 
What I have got so far: At - As = 112 
At = 135 
135 - As = 112
I have corrected as follows
112 = (15-2x) (9-2x)
4x^2 - 30x - 18x + 135 = 112
4x^2 - 48x + 135 - 112 = 0
4x^2 - 48x + 23 = 0
Two solutions, found by the quadratic equation a=4; b=-48, c=23
x=11.5 
and the more reasonable solution is
x=.5 cm
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