If C.P. of 27 books is equal to S.P of 30 books , then your gain or loss is ? Pick:
A) 23 1/3 gain %	B) 30 10/23 loss %	C) 10% loss %	D) 30 1/3 loss %	E) 40 1/3 loss %
Say the cost price of 27 books is $27 so $1 for a book.   The cost of 30 books would be $30, and the selling price of 30 books would be 27$, hence the loss = ($30 - $27)/$30 = 10%.   Answer: 10% loss %.
<result>C</result>
If C.P. of 27 books is equal to S.P of 30 books , then your gain or loss is ?