13 different biology books and 8 different chemistry books lie on a shelf. In how many ways can a student pick 2 books of each type?	Pick:
A) 80 B) 160 C) 720 D) 1100 E) 2184

Rationale: "no . of ways of picking 2 biology books ( from 13 books ) = 13 c 2 = ( 13 * 12 ) / 2 = 78 no . of ways of picking 2 chemistry books ( from 8 books ) = 8 c 2 = ( 8 * 7 ) / 2 = 28 total ways of picking 2 books of each type = 78 * 28 = 2184 ( option e )"
Answer: E