NCERT Class XII Mathematics Chapter - - Solutions
© examsnet.com
Question : 79
Total: 101
Find the probability of throwing at most 2 sixes in 6 throws of a single die.
Solution:
Let p be the probability of success that is getting six =
⇒ q = 1 − p = 1 −
=
Let X has a binomial distribution withn = 6 , p =
, q =
∴ P ( X = r ) = n C r ( q ) n − r p r
∴ Required probability = P(getting atmost 2 sixes)
= P(X ≤ 2) = P(X = 0) + P(X = 1) + P(X = 2)
= 6 C 0 q 6 p 0 + 6 C 1 q 5 p 1 + 6 C 2 q 4 p 2 = 1 × (
) 6 × 1 + 6 × (
) 5 ×
+ 15 × (
) 4 × (
) 2 =
(
) 4
Let X has a binomial distribution with
∴ Required probability = P(getting atmost 2 sixes)
= P(X ≤ 2) = P(X = 0) + P(X = 1) + P(X = 2)
© examsnet.com
Go to Question: