Let S = {1, 2, … , 20). A and B subset of S is said to be “nice”, if the sum of the elements of B is 203. Then the probability that a randomly chosen subset of S is “nice” is

Let S = {1, 2, ... , 20). A and B subset of S is said to be "nice", if the sum of the elements of B is 203. Then the probability that a randomly chosen subset of S is "nice" is

  1. A

    5/220

  2. B

    7/220

  3. C

    4/220

  4. D

     6/220

    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:

    S={1,2,,20}

    Total no. of subsets =220

    We have, 1+2++20=20(21)2=210

    Sum of elements will be 203 if we would not choose 7 or elements which are giving sum 7.

    Elements giving sum 7 are (1, 6), (2, 5), (3, 4), (1, 2, 4) Thus, a subset will be 'nice' if we didn't choose these 5 outcomes.

      Required probability (subset choosen is 'nice') =5220

     

    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.