Every body in a room shakes hands with everybody  else. The total number of hand shakes is 66. The total number of persons in the room is

Every body in a room shakes hands with everybody  else. The total number of hand shakes is 66. The total number of persons in the room is

  1. A

    11

  2. B

    12

  3. C

    13

  4. D

    14

    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:

    Let total number of persons be n.
    Since, total number of hand shakes = 66

            nC2    =66n(n1)2=66    n2n132    =0    (n12)(n+11)    =0        n    =12    [n cannot be negative ]

    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.