Question

 

Four upper level undergraduate students are available to serve on a committee.

 

Student	Gender	Year in school
1	M	Junior
2	M	Senior
3	F	Junior
4	F	Senior

 

Two students will be selected at random to serve on the committee. Let

A: The students selected are of the same gender.

B: The students selected are the same year in school.

Find the probability of A ∪ B .

Answer 1

1/8

......................

Answer 2

the correct answer is actually 2/3  

P (AuB)= P(A)+P(B)-P(AB)

                  2/6+2/6-0/6= 4/6= 2/3