The probability that a student is not a swimmer is $\frac{1}{5}$. Then the probability that out of live students, four are swimmers is :
Answer & explanation
Correct answer: option 1
The correct answer is option (1) → ${^5C}_4\left(\frac{4}{5}\right)^4\frac{1}{5}$
$P(S)=\frac{4}{5},P(\overline{S})=\frac{1}{5}$
then probability of 4 out of 5 to be swimmers
$⇒{^5C}_4\left(\frac{4}{5}\right)^4\frac{1}{5}$