Each side of a rectangle is increased by 100% .By what percentage does the area increase? Pick
A) 300 %  B) 400 %  C) 500 %  D) 200 %  E) 600 %

Rationale: original area = a * b where a and b are sides after increase in side increase in area will be = ( ( ( 2 a * 2 b ) - ( a * b ) ) * 100 ) / ( a * b ) = 300 % answer : a
Answer: A