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 : |
${^5C}_4\left(\frac{4}{5}\right)^4\frac{1}{5}$ $\left(\frac{4}{5}\right)^4\frac{1}{5}$ ${^5C}_4\left(\frac{1}{5}\right)^4\frac{4}{5}$ $\left(\frac{1}{5}\right)^4\frac{4}{5}$ |
${^5C}_4\left(\frac{4}{5}\right)^4\frac{1}{5}$ |