Question

Suppose S and T are mutually exclusive events find P(S or T) if P(S)=1/3 and P(T)=5/12

Answer 1

The value of P(S or T) is 3/4.

Explanation:

It is given that S and T are mutually exclusive events. It means intersection of S and T is 0.

`S\cap T=0`

`P(S\cap T)=0`

We need to find the value of P(S or T). It means we have to find the probability of union of S and T.

`P(S\cup T)=P(S)+P(T)-P(S\cap T)`

Substitute the given values in the above formula.

`P(S\cup T)=(1)/(3)+(5)/(12)-(0)`

`P(S\cup T)=(4+5)/(12)`

`P(S\cup T)=(9)/(12)`

`P(S\cup T)=(3)/(4)`

Therefore the value of P(S or T) is 3/4.

Answer 2

P(S or T)= 3/4

Explanation:

Given:

S and T are mutually exclusive events

find P(S or T)

P(S or T)= P(S) + P(T)

= 1/3 +5/12

=4+5/12

=9/12

=3/4 !