A committee of two persons is selected from two men and two women. What is the probability that the committee will have one man ?
The total number of persons $=2+2=4 .$ Out of these four person, two can be selected in $^{4} C _{2}$ ways.
One man in the committee means that there is one woman. One man out of $2$ can be selected in $^{2} C _{1}$ ways and one woman out of $2$ can be selected in $^{2} C _{1}$ ways.
Together they can be selected in $^{2} C _{1} \times^{2} C _{1}$ ways.
Therefore $P$ (One man) $=\frac{^{2} C _{1} \times^{2} C _{1}}{^{4} C _{2}}$ $=\frac{2 \times 2}{2 \times 3}=\frac{2}{3}$
In a regular $15$ -sided polygon with all its diagonals drawn, a diagonal is chosen at random. The probability that it is neither a shortest diagonal nor a longest diagonal is
A debate club consists of $6$ girls and $4$ boys. A team of $4$ members is to be selected from this club including the selection of a captain (from among these $4$ memiers) for the team. If the team has to include at most one boy, then the number of ways of selecting the team is
A bag contains $4$ white and $3$ red balls. Two draws of one ball each are made without replacement. Then the probability that both the balls are red is
There are four machines and it is known that exactly two of them are faulty. They are tested, one by one, is a random order till both the faulty machines are identified. Then the probability that only two tests are needed is
Ten students are seated at random in a row. The probability that two particular students are not seated side by side is