Aptitude - Area - Discussion

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The percentage increase in the area of a rectangle, if each of its sides is increased by 20% is:

[A].

40%

[B].

42%

[C].

44%

[D].

46%

Answer: Option C

Explanation:

Let original length = x metres and original breadth = y metres.

Original area = (xy) m².

New length = 120 x m = 6 x m.

100 5

New breadth = 120 y m = 6 y m.

100 5

New Area = 6 x x 6 y m² = 36 xy m².

5 5 25

Increase % = 11 xy x 1 x 100 % = 44%.

25 xy

Chandra said: (Tue, Aug 17, 2010 04:16:39 PM)

when there is an increase in sides of a figure, the net increase in its area is x+y+xy/100 % So here 20% +20% + 20x20/100% = 44%

Bhupendra said: (Wed, Aug 18, 2010 12:49:26 PM)

Let it be a squire then suppose side is x then area =x^2 new side is= (6x/5) then area= 36x^2/25 Now diff in area= 36x^2/25-x^2= (11x^2/25) then % increase in area is = (11x^2/25)*100/x^2= 44 ans