The C.P of 20 books is equal to the S.P of 30 books. Find his gain% or loss%?	Pick.
A) 63.33 %
B) 34.33 %
C) 33.33 %
D) 31.33 %
E) 36.33 %

Rationale: explanation : 20 cp = 30 sp 30 - - - 10 cp loss 100 - - - ? = > 33.33 % loss answer : c
Answer: C