Anic, let's find the solution:
P (A) = 0.18
P (A does not occur) = 1 - 0.18 = 0.82
P (B) = 0.64
P (B does not occur) = 1 - 0.64 = 0.36
a. Compute the probability that B occurs or A does not occur (or both).
A and B are mutually exclusive events, therefore:
P (B or A does not occur) = P(B) + P (A does not occur) - P (B and A does not occur)
P (B or A does not occur) = 0.64 + 0.82 - (0.64 * 0.82)
P (B or A does not occur) = 0.64 + 0.82 - 0.5248
P (B or A does not occur) =0.9352
b. Compute the probability that either B occurs without A occurring or A and B both occur.
P (B or A and B) = P(B) + P (A and B) - P (B and A and B)
P (B or A and B) = 0.64 + (0.64 * 0.18) - (0.64 * 0.1152)
P (B or A and B) = 0.64 + 0.1152 - (0.64 * 0.1152)
P (B or A and B) = 0.64 + 0.1152 - 0.0737
P (B or A and B) = 0.6815