Rahim bought 42 books for Rs.520 from one shop and 22 books for Rs.248 from another. What is the average price he paid per book ?  Choose the correct choice from the following options
A) s . 17  B) s . 18  C) s . 12  D) s . 11  E) s . 10

Rationale: "average price per book = ( 520 + 248 ) / ( 42 + 22 ) = 768 / 64 = rs . 12 answer : c"
Answer: C