\ \ \ \ Let

E

and

F

be mutually exclusive events in the sample space of an experiment. Suppose that the experiment is repeated until either event

E

or event

F

occurs. Show that the probability that event

E

occurs before event

F

is

P(E)/(P(E)+P(F))

.

4. Let E and F be mutually exclusive events in the sample space of an expermment. Suppose that the experiment is repeated until either event E or event F occurs. Show that the probability that event E occurs before event F is P(E)/[P(E)+P(F)]