# MDM4U Probability with equally-likely outcomes 2017-10-02

When each outcome in a sample space is equally likely,

$P(x)=\frac{1}{n(S)}$

for each $x \in S$.

For any event $A \subseteq S$,

$P(A) = \frac{n(A)}{n(S)}$

We often say something like, “We get the probability by counting the number of ways the event can happen and dividing by the number of ways anything can happen.”

For homework complete Page 325 #6, 9, 10.