There are 9 books on a shelf that consist of 2 paperback books and 7 hardback books. If 4 books are selected at random without replacement, how many different combinations are there which include at least one paperback book?
Answers:  A) 85  B) 91  C) 97  D) 103  E) 110
The total number of ways to select 4 books is 9C4 = 126   The number of ways which do not include any paperbacks is 7C4 = 35   The number of combinations with at least one paperback is  126-35= 
<gadget id="calculator"> 126-35</gadget>
<output>91</output>
91   The answer is 91.
<result>B</result>
There are 9 books on a shelf that consist of 2 paperback books and 7 hardback books. If 4 books are selected at random without replacement, how many different combinations are there which include at least one paperback book?