If P(A∩B)=0.12,P(A)=0.33, and P(B)=0.43, find P(A∪B).

Question

anonymous · Answer

A
0.75

B
0.60

C
0.69

D
0.64

I don't know how to do these (at all) :)

diyadiya · Answer

$$\huge P(A∪B).= P(A) + P(B) - P(A∩B)$$

diyadiya · Answer

Can you do it now?

anonymous · Answer

0.64?

diyadiya · Answer

Yes! You got it right :)

anonymous · Answer

is that all, just plug into the formula?

diyadiya · Answer

Yup! thats all :)

anonymous · Answer

thanks! (:

diyadiya · Answer

Anytime :)

anonymous · Answer

Do you see how this is the same as that selecting a card from the deck question?

anonymous · Answer

I don't see the similarity. I'm horrible at word problems :/ I'm better with equations

anonymous · Answer

In both cases, the probability of an OR situation is to add the probabilities of each and subtract the probability of both happening together. IOW, the union = the addition - the intersection.

anonymous · Answer

ohh, so its the same formula to solve to get the answer. Just in a different format?

anonymous · Answer

$$A \cup B $$ means = A OR B (the union of sets) -> add
$$A \cap B$$ means A AND B (the intersection of sets) -> multiply

anonymous · Answer

There are other things to consider, e.g. independent events, mutually exclusive events, etc.

anonymous · Answer

Is this for an intro probability and statistics course? If so, try this website: http://stattrek.com/probability/probability-rules.aspx?Tutorial=Stat