In a single roll of a six-sided dice, what is the probability of rolling a three or an even number?
You have 2 events: A & B.
Probability of rolling a three
Probability of rolling an even number
We have two events A and B:
A being an even number 2 4 6.
B being a 3.
Since this is an A or B event occurring, we have a union of events. i.e.
So we have:
We could have obtained this result directly by considering the 2 events as one event:
An even number and 3 is four favourable outcomes, so: