### Video Transcript

Two mutually exclusive events π΄
and π΅ have probabilities the probability of π΄ equals one-tenth and the probability
of π΅ equals one-fifth. Find the probability of π΄ union
π΅.

These two events are mutually
exclusive, and so we can recall the addition rule. The probability of π΄ union π΅ is
the sum of the individual probabilities. Itβs the probability of π΄ plus the
probability of π΅. For this question then, we have
that the probability of π΄ union π΅ is one-tenth plus one-fifth. We write that fraction of one-fifth
as an equivalent fraction with the denominator of 10. Itβs 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 π΄ union π΅ is
three-tenths.