Q20 of 99 Page 264

If the length is increased by 10% and breadth is decreased by 10% of a rectangle, then what percent of area will be increased or decreased?

Let original length and breadth be L and B respectively.

Original Area = L × B


10% increase in length corresponds to 0.1L.


10% decrease in length corresponds to 0.1B.


New length = 1.1L


New breadth = 0.9B


New area = (1.1L)(0.9B) = 0.99LB


%change in area =


= = - 1%


So 1% area will be decreased.


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