
# Given probabilities
P_A1 = 0.3
P_A2 = 0.2
P_A3 = 0.2

P_A1_B = 0.3 * 0.6
P_A2_B = 0.2 * 0.7
P_A3_B = 0.2 * 0.8

# Calculate the desired probability
P_B_given_A1_A2_A3 = (P_A1_B + P_A2_B + P_A3_B) / (P_A1 + P_A2 + P_A3)

print(P_B_given_A1_A2_A3)
