Plz help on this..
A class has 12 boys and 4 girls. Suppose three students are selected at random from the class. Find the probability P that they are all boys using Multiplication theorem for conditional probability.
Thnx in advance
Plz help on this..
A class has 12 boys and 4 girls. Suppose three students are selected at random from the class. Find the probability P that they are all boys using Multiplication theorem for conditional probability.
Thnx in advance
There are $\displaystyle {12 \choose 3}$ ways of picking 3 boys.
AND there are $\displaystyle {4 \choose 0}$ ways of picking 0 girls.
There are $\displaystyle {16 \choose 3}$ ways of picking three students.
So the probability is $\displaystyle \frac{{12 \choose 3} {4 \choose 0}}{{16 \choose 3}}=\frac{11}{28}$