QUESTION 1 Suppose A and B are events in a sample space S a

QUESTION 1 ------ Suppose A and B are events in a sample space S, and P(A|B) = 1/2 and P(B) = 1/3. P(A B) = 1/6

True

False

QUESTION 2 -----

A club has seven members. Three are to be chosen to go as a group to a national meeting.

How many distinct groups of three can be chosen?

Solution

1) We Know that If A and B are any two events in an experiment then

                                                      P(A|B)=P(A B)/P(B)

                                                                =[1/6]/[1/3]

                                                                =1/2

The answer for the first question is TRUE

2)The distinct groups of three can be choosen is =7C3

                                                                      =(7!)/(3!)(7-3)!

                                                                      =(7!)/(4!)

                                                                      =(7*6*5*4*3*2*1)/(3*2*1)(4*3*2*1)

by doing cancellation we get

                                             =(7*6*5)/(3*2*1)

                                             =7*5

                                             =35