Video Transcript
Two mutually exclusive events 𝐴
and 𝐵 have probabilities the probability of 𝐴 equals one-tenth and the probability
of 𝐵 equals one-fifth. Find the probability of 𝐴 union
𝐵.
These two events are mutually
exclusive, and so we can recall the addition rule. The probability of 𝐴 union 𝐵 is
the sum of the individual probabilities. It’s the probability of 𝐴 plus the
probability of 𝐵. For this question then, we have
that the probability of 𝐴 union 𝐵 is one-tenth plus one-fifth. We write that fraction of one-fifth
as an equivalent fraction with the denominator of 10. It’s two-tenths. And then summing the two
probabilities gives three-tenths. By applying the addition rule for
mutually exclusive events then, we found that the probability of 𝐴 union 𝐵 is
three-tenths.
