finite math help

Question

An experiment has the sample space S = { O₁, O₂, O₃, O₄, O₅, O₆}. Each outcome O_i is assigned a weight w_i so that outcomes O₁, O₂, O₃, and O₄ each have the same weight while w₅ = .60 and w₆ = .20 . 

Answer 1

Weights W₁ + W₂ + W₃ + W₄ = 1 - (W₅ + W₆) = 1 - (0.60 + 0.20) = 0.20.

So, W₁ = W₂ = W₃ = W₄ = 0.20/4 = 0.05

Pr(A∩B^c) = Pr({O_1,O_2,O₃}∩{O₁,O₃,O₆}) = Pr{O₁,O₃} = 0.05 + 0.05 = 0.10