The length of a rectangular plot is increased by 40%. By what percentage must its breadth be decreased so that the area stays the same?
Correct answer B. 28 4/7%
Explanation
Breadth must become 1/1.4 = 5/7 of the original. Decrease = 2/7 = 28 4/7%. Taking 40% of the new breadth instead of the old is a common mistake.
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