The C.P of 30 books is equal to the S.P of 40 books. Find his gain% or loss%? Choose the correct answer
A) 23%
B) 24%
C) 25%
D) 50%
E) 40%
explanation:   30 25%P = 40 SP   40 --- 10 25%P loss   100 --- ? =&gt; 25% loss   Answer: 25%
<result>C</result>
The C.P of 30 books is equal to the S.P of 40 books. Find his gain% or loss%?