Please help with probability Q;

Question

Suppose Rolly randomly picks a movie to

watch, and then randomly picks a second

movie without putting the first movie back

on the shelf. Determine the probability of

each of the following scenarios:

a) Rolly will watch a Connery movie

followed by a Moore movie.

b) Rolly will watch two consecutive Dalton

movies.

c) Rolly will watch three consecutive Craig

movies.

Answer 1

Hi,

total number of movies =22

a) Probability of picking a Connery movie =

number of Connery movies/ total number of movies=6/22

probability of picking the second (Moore)movie ( now note that the total number of movies becomes 21 because one movie has been picked already and not put back) would be = number of Moore movies/21

= 7/21

probability of watching one followed by the other

=(6/22)*(7/21)

=3/11* 1/3

= 1/11

{hint- when both events occur multiply the probabilities }

b) two consecutive Dalton movies

(2/22)* (1/21)

Note that the second time the total number of movies has decreased by 1 and the number of Dalton movies has also decreased by 1

c) 3 consecutive Craig movies- there are only 2 Craig movies so illy can’t pick a third Craig movie so probability would be 0

(2/22)*(1/21)*0

=0