There are 4 books on a shelf, of which 3 are paperbacks and 6 are hardbacks. How many possible selections of 4 books from this shelf include at least one paperback?	Select.
A) a) 40	B) b) 45	C) c) 50	D) d) 55	E) e) 111
approach 1   at-least 1 paper back = total - no paper back   9c4-6c4 = 111   approach 2   at-least 1 paper back = 1 paper back , 3 hard back or 2 paper back 2 hard back   = 3c1*6c3+3c2*6c2 + 3c3*6c1 = 111   Answer is e) 111
<result>E</result>
There are 4 books on a shelf, of which 3 are paperbacks and 6 are hardbacks. How many possible selections of 4 books from this shelf include at least one paperback?