A customer enters a supermarket.
The probability that the customer buys bread is 0.6,
the probability that he buys milk is 0.5,
and that he buys both bread and milk is 0.3.
What is the probability that the customer would buy either bread or milk or both?
You are expected to know this formula:
. . . P(B U M) .= .P(B) + P(M) - P(B ∩ M)
Therefore: .P(B U M) .= .0.6 + 0.5 - 0.3 .= .0.8