1.5. Mutually Inclusive Events http://www.ck12.org
If eventsAandBshare some overlap in the Venn diagram, they may be consideredmutually inclusive events. Look
at the diagrams below to see how these events can occur. Mutually inclusive events can occur at the same time. Say,
for example, you wanted to pick a number from 1 to 10 that is less than 4 and pick an even number. Let eventAbe
picking a number less than 4 and eventBbe picking an even number.
A={ 1 , 2 , 3 }
P(A) =
3
10
B={ 2 , 4 , 6 , 8 , 10 }
P(B) =
5
10
P(AandB) =1
10
The reason whyP(AandB) = 101 is because there is only 1 number from 1 to 10 that is both less than 4 and even,
and that number is 2.
When representing this on the Venn diagram, we would see something like the following:
Mutually inclusive events, remember, can occur at the same time. Look at the Venn diagram below. What do you
think we need to do in order to calculate the probability ofA∪Bjust from looking at this diagram?