If the cost price of 12 pens is equal to the selling price of 8 pens, the gain percent is: Choose one.
A) 25%  B) 33 1/3 %  C) 50%  D) 66 2/3 %  E) none
Let C.P. of each pen be Re. 1.   Then, C.P. of 8 pens = Rs. 8; S.P. of 8 pens = Rs. 12.   Gain % = 4/8 * 100= 
<gadget id="calculator">4/8 * 100</gadget>
<output>50</output>
50%   ANSWER:50%
<result>C</result>
If the cost price of 12 pens is equal to the selling price of 8 pens, the gain percent is: