There are 3 fictions and 6 non-fictions. How many cases are there such that 2 fictions and 2 non-fictions are selected from them? Answers: A) 90 B) 120 C) 45 D) 180 E) 200
Number of ways of selecting 2 fiction books = 3452   Number of ways of selecting 2 non fiction books = 6452   3452 * 6452 = 3 * 15= 
<gadget id="calculator">3 * 15</gadget>
<output>45</output>
45   Answer: 45
<result>C</result>
There are 3 fictions and 6 non-fictions. How many cases are there such that 2 fictions and 2 non-fictions are selected from them?