How do you find probabilities of compound events?

1 Answer
MeneerNask
Nov 18, 2017

Depends on the relation between the events.

Explanation:

Example1: probability of rolling a 3 or a 5 with one throw.
P(3)=1/6, P(5)=1/6
Since this is an exclusive OR situation we ADD the probabilities:
P(3or5)=P(3)+P(5)=1/6+1/6=1/3

Example2: probability of first rolling a 3, and then a 5 with one die.
1st roll: P(3)=1/6, 2nd roll: P(5)=1/6
Since this is an AND situation, we MULTIPLY:
P(3,5)=1/6xx1/6=1/36
Note: if the question were about 'a 3 and a 5' (in any order) we'd have to add: P(5,3)=1/36

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