8C3 [Select any four] - 7C3 [Select all hard backs] = 21
There are 8 books in a shelf that consist of 1 paperback books and 7 hardback books. If 3 books are selected at random without replacement, how many different combinations are there that at least one paperback book is selected?
Options:
- 21
- 45
- 50
- 55
- 60