Question

The probability that a student entering a university will graduate is 0.4. Find the probability that out of 3 students of the university only one will graduate .

Answer 1

Let X be the number of students that graduate from among 3 students.
Let p=probability that a student entering a university  will graduate.

Here , n =3, p=0.4 and q = 0.6
Hence, the distribution is given by

\[P(X = r) =^{3}{}{C}_r \left( 0 . 4 \right)^r \left( 0 . 6 \right)^{3 - r} , r = 0, 1, 2, 3\]

\[  P(X = 1) = 3(0 . 4)(0 . 36) = 0 . 432\]