Aptitude Hack#78(12-5-19)

Question:

If each side of a square is increased by 25%, find the percentage change in its area

   A )   56.45%
   B )   56.25%   
   C )   55.25%
   D )   52.25%


Answer: B) 56.25%

Explanation : 

Let each side of the square be a.

 Then, area = a２.

New side =(125a/100)
 =(5a/4).

 New area = (5a/4)２  =(25a２)/16.

Increase in area = ((25 a２)/16)-a２
 =(9a２)/16.

Increase% = [((9a2)/16)*(1/a2)*100] %
 = 56.25%.