To find the probability of drawing at least 8 spades, we can calculate the probability of drawing exactly 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 spades, and then add them up.
Let's calculate the probability of drawing exactly 8 spades:
P(8 spades) = C(20, 8) * (1/4)^8 * (3/4)^(20-8)
Similarly, we can calculate the probabilities for drawing 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 spades.
Finally, we add up all these probabilities to find the probability of drawing at least 8 spades.!