The C.P of 10 pens is equal to the S.P of 14 pens. Find his gain % or loss%? Choose the correct answer
A) loss 16 2/8%	B) loss 28.57%	C) loss 16 2/3%	D) loss 18 2/3%	E) loss 16 25%
10 CP = 14 SP   14 --- 4 CP loss   100 --- ? =&gt; 28.57% loss   Answer:loss 28.57%
<result>B</result>
The C.P of 10 pens is equal to the S.P of 14 pens. Find his gain % or loss%?