The C.P of 15 books is equal to the S.P of 20 books. Find his gain% or loss%?  Answers:
A) 28% B) 25% C) 24% D) 23% E) 27%
explanation:   15 CP = 20 SP   20 --- 5 CP loss   100 --- ? =&gt; 25% loss   Answer: 25%
<result>B</result>
The C.P of 15 books is equal to the S.P of 20 books. Find his gain% or loss%?