It is known that 10% of certain articles manufactured are defective. What is the probability that in a random sample of 12 such articles, 9 are defective?

Explanation

required probability is

`P(9/12) = .^12C_9(1/10)^9(9/10)^3`

`= (12*11*10)/(3*2) * (1/10)^9(9/10)^3`

`= 22* 9^3/10^11 `

answer