# Suppose S and T are mutually exclusive events. Find P(S or T) if P(S) = 1/3 and P(T) = 5/12?

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3/4

7/18

5/36

3/4

7/18

5/36

##### 2 Answers

Apr 20, 2017

In an OR situation you may ADD

#### Explanation:

Apr 24, 2017

# P(S uu T) = 3/4 #

#### Explanation:

We use the following fundamental definition from Probability and Set Theory:

# P(A uu B) = P(A) + P(B) - P(A nn B) #

And if we apply this to our problem we have:

# P(S uu T) = P(S) + P(T) - P(S nn T) #

# " " = 1/3 + 5/12 - P(S nn T) #

# " " = 3/4 - P(S nn T) #

Now we are told that

# P(S nn T) =0 #

Hence,

# P(S uu T) = 3/4 #