If C.P. of 28 books is equal to S.P of 30 books , then your gain or loss is ?
Choose the correct choice from the following choices:
A) 23 1/3 gain % B) 30 10/23 loss % C) 6.67 loss % D) 30 1/3 loss % E) 40 1/3 loss %
Say the cost price of 28 books is $28 so $1 for a book.   The cost of 30 books would be $30, and the selling price of 30 books would be 28$, hence the loss = ($30 - $28)/$30 = ~6.67%.   Answer: 6.67 loss %.
<result>C</result>
If C.P. of 28 books is equal to S.P of 30 books , then your gain or loss is ?