Answer:
B.
Step-by-step explanation:
P(something not happening)+P(something happening)=1 or 100%.
So if we have
P(something not happening)+40%=100%
Then the P(something not happening)=60% since 60%+40%=100%.
Yes I was using the event="something not happening" as the complement of something happening.
In fancy notation, some people might write:
[tex]P(A)+P(A')=1[/tex]
or
[tex]P(A)+P(A^c)=1[/tex]
