A committee of two persons is selected from two men and two women. What is the probability that the committee will have one man?
Show Hint
For committee-selection problems, use combinations because the order of selection is irrelevant. Always count favourable committees and total committees separately before computing probability.
Concept:
When selecting a committee, order does not matter. Therefore, combinations are used.
The probability is
\[
P(E)
=
\frac{\text{Number of favourable committees}}
{\text{Total number of committees}}.
\]
Step 1: Find the total number of committees.
There are
\[
2+2=4
\]
people.
The number of ways to choose a committee of two persons is
\[
{}^{4}C_{2}
=
\frac{4!}{2!2!}
=
6.
\]
Thus,
\[
n(S)=6.
\]
Step 2: Find the number of favourable committees.
The committee must contain exactly one man.
Choose
\[
1
\]
man from
\[
2
\]
men:
\[
{}^{2}C_{1}=2.
\]
Choose
\[
1
\]
woman from
\[
2
\]
women:
\[
{}^{2}C_{1}=2.
\]
Therefore,
\[
n(E)
=
{}^{2}C_{1}\times{}^{2}C_{1}
=
2\times2
=
4.
\]
Step 3: Compute the probability.
\[
P(E)
=
\frac{4}{6}
=
\frac{2}{3}.
\]
Conclusion:
Hence, the probability that the committee contains exactly one man is
\[
\boxed{\frac{2}{3}}.
\]