The C.P of 10 pens is equal to the S.P of 12 pens. Find his gain % or loss%?  Select:
A) 16 2/8% B) 16 6/3% C) 16 2/3% D) 18 2/3% E) 16 25%
10 16 2/3%P = 12 SP   12 --- 2 16 2/3%P loss   100 --- ? =&gt; 16 2/3%   Answer:16 2/3%
<result>C</result>
The C.P of 10 pens is equal to the S.P of 12 pens. Find his gain % or loss%?