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## Comment on

Applying the OR Rule## Hi,

Is the mutually exclusive events and independent events means the same?

So if the events are independent then is P(event A and Event B)=0.

Plz can you clarify with this question:

"There is an 80% chance David will eat a healthy breakfast and a 25% chance that it will rain. If these events are independent, what is the probability that David will eat a healthy breakfast OR that it will rain"

## "Mutually Exclusive" does not

"Mutually Exclusive" does not mean the same as "Independent"

If events A and B are mutually exclusive, then P(A and B) = 0

If events A and B are independent, then P(A and B) = P(A) x P(B)

Now onto your question...

We want P(David eats a healthy breakfast OR it rains)

We know that P(A OR B) = P(A) + P(B) - P(A and B)

So, P(David eats a healthy breakfast OR it rains) = P(David eats healthy breakfast) + P(it rains) - P(eats healthy breakfast AND that it rains)

= 0.8 + 0.25 - (0.8 x 0.25)

= 0.8 + 0.25 - (0.2)

= 0.85

Does that help?

Cheers,

Brent

## Thanks Brent