Question 170089
A small garden measures 8 feet by 10 feet. A uniform border around the garden increases the total area to 143 square feet. What is the width of the border?
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It's exactly 3 feet.  11 x 13 = 143
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New area = (8+2x)(10+2x) = 143
80 + 36x + 4x^2 = 143
4x^2 + 36x - 63 = 0
x = [-36 +- sqrt(36^2 - 4*4*-63]/8 
x = [-36 +- sqrt(2304)]/8 
x = [-36 +- 48]/8
Positive solution: 
x = 1.5 ft. (width of the border)
1.5 ft on all sides increases the width and length by 3 feet.
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The other solver seems to have read it as "increases it by 143", and his solution is correct for that.