A carton contains 20 bulbs, 5 of which are defective. The probability that, if a sample of 3 bulbs is chosen at random from the carton 2 will be defective, is 

A carton contains 20 bulbs, 5 of which are defective. The probability that, if a sample of 3 bulbs is chosen at random from the carton 2 will be defective, is 

  1. A

    1/6

  2. B

    3/64

  3. C

    9/64

  4. D

    2/3

    Register to Get Free Mock Test and Study Material

    +91

    Verify OTP Code (required)

    I agree to the terms and conditions and privacy policy.

    Solution:

     We have, 

    p = Probability that a bulb is defective =520=14

     q=1p=114=34

    Let X denote the number of defective bulbs in a sample of 3 bulbs. Then, X is a binomial variate with parameter n=3 and p=14 such that

    P(X=r)=3Cr14r343r P(X=2)=3C214234=964

    Chat on WhatsApp Call Infinity Learn

      Register to Get Free Mock Test and Study Material

      +91

      Verify OTP Code (required)

      I agree to the terms and conditions and privacy policy.