A number is increased by 70 % and then decreased by 70 %. Find the net increase or decrease per cent.  Select the correct option:
A) 49 % B) 18 % C) 17 % D) 13 % E) 16 %

Rationale: let the number be 100 . increase in the number = 70 % = 70 % of 100 = ( 70 / 100 ã — 100 ) = 70 therefore , increased number = 100 + 70 = 170 this number is decreased by 70 % therefore , decrease in number = 70 % of 170 = ( 70 / 100 ã — 170 ) = 11900 / 100 = 119 therefore , new number = 170 - 119 = 51 thus , net decreases = 100 - 51 = 49 hence , net percentage decrease = ( 49 / 100 ã — 100 ) % = ( 4900 / 100 ) % = 49 % answer : a
Answer: A