hello i need help with answering the following Probability questions for my sons homework so i can
check his answers.
1. Three men and two women are semifinalists in a lottery. From this group, three finalists are to be
selected by a drawing. What is the probability that all three finalists will be men? (Round your answer to
four decimal places.)
There are total 5 persons. We can select 3 persons in 5 C3 ways from 5 persons. There are 3 men and
we can select 3 form them in 3 C3 ways. Hence, the probability that all the finalists will be men is given
by
C3 3 C3 3  2 11 2 1


  0.1
5
C3 5 C2 1 2  3  5  4 10
3
P=
2.A task force studying sex discrimination wishes to establish a subcommittee. If the subcommittee is to
consist of 11 members chosen at random from a group of 17 men and 17 women, find the probability
that the subcommittee consists of the following?
(a) 4 men and 7 women (Round your answer to two decimal places.)
There are 34 persons. We can select 11 persons in
17 men and 7 women can be selected in
17
=
17
34
C11 ways. 4 men can be selected in
C4 17 C7
34
C11
2380  19448
286097760
= 0.000076295
(b) all women (Round your answer to seven decimal places.)
We Can select 11 women in
17
C11 ways from 17 women. Hence, required probability
17
P=
C11

34
C11
17
34
C 4 ways from
C7 ways from 17 women. Hence, required probability
17 16 15 14 17 16 15 14 13 12 11

1 2  3  4
1 2  3  4  5  6  7
=
34  33  32  31 30  29  28  27  26  25  24
1 2  3  4  5  6  7  8  9 10 11
=
17
C6
12376

=0.000043257
C11 286097760
4. The probability that daughters of a mother who attends church regularly will also attend church
regularly is 0.7, whereas the probability that daughters of a mother who does not attend regularly will
attend regularly is 0.4. If a woman attends church regularly and has one daughter who in turn has one
daughter, what is the probability that the granddaughter attends church regularly?
Probability that the daughter will attend church is 0.7 as mother is attending church regularly. The
granddaughter will attend church will be 0.7*0.7 =0.49 if her mother also attends church. If mother of
granddaughter does not attend church, the probability that granddaughter will attend church will be
0.4*0.7=0.28. Hence, overall probability = 0.49+0.28 =0.77
5. The probability that daughters of a mother who attends church regularly will also attend church
regularly is 0.5, whereas the probability that daughters of a mother who does not attend regularly will
attend regularly is 0.3.
Question is not complete.