There are 9 books on a shelf that consist of 2 paperback…

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?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #5185