A box contains 17 ​transistors, 3 of which are defective. If 3 are selected at​ random, find the probability that
a. All are defective.
b. None are defective.

Respuesta :

b none are defective

Use Binomial Theorem
[tex]P(x=k) = (nCk) p^k (1-p)^{n-k}[/tex]
Where k is number that are defective, n is total selected (3), and p is probability that a transistor is defective (3/17).

a) All are defective means k = 3
[tex]P = (3C3) (\frac{3}{17})^3 (\frac{14}{17})^0 = (\frac{3}{17})^3 = 0.0055[/tex]

b) None are defective means k = 0
[tex]P = (3C0) (\frac{3}{17})^0 (\frac{14}{17})^3 = (\frac{14}{17})^3 = 0.5585[/tex]