Answer:
6)
8 nCr 4 = 8 * 7 * 6 * 5 / 4! = 70
P = 1 - 12/70 ≈ 0.83
7)
7.7 - 5 = 2.7 --> Answer c.
8)
3 5/8 - 1 = 2 5/8 --> Answer a.
