A number is increased by 20 % and then decreased by 20 %. Find the net increase or decrease per cent. Choose the correct choice from the following.
A) 9%  B) 8%  C) 7%  D) 3%  E) 4%
Let the number be 100.   Increase in the number = 20 % = 20 % of 100   = (20/100 Ã— 100)   = 20   Therefore, increased number = 100 + 20= 
<gadget id="calculator">100 + 20</gadget>
<output>120</output>
120   This number is decreased by 20 %   Therefore, decrease in number= 20 % of 120   = (20/100 Ã— 120)   = 2400/100= 
<gadget id="calculator">2400/100</gadget>
<output>24</output>
24   Therefore, new number= 120 - 24= 
<gadget id="calculator">120 - 24</gadget>
<output>96</output>
96   Thus, net decreases= 100 - 96= 
<gadget id="calculator">100 - 96</gadget>
<output>4</output>
4   Hence, net percentage decrease= (4/100 Ã— 100) %   = (400/100)= 
<gadget id="calculator">(400/100)</gadget>
<output>4</output>
4 %   Answer:4%
<result>E</result>
A number is increased by 20 % and then decreased by 20 %. Find the net increase or decrease per cent.