Anonymous asked in Science & MathematicsMathematics · 9 years ago

4 people talked on the phone. each person talked to everyone ONCE. how many conversations took place?

7 Answers

  • Anonymous
    9 years ago
    Favorite Answer

    That would be...

    6 conversations!

    Use combination formula...



    n = 4 and r = 2, so 4C2 = 6

    I hope this helps!

    Source(s): Σ
  • 9 years ago

    Call the people A, B, C and D

    A talks to B, then C then D. That's 3 conversations.

    B can't talk to A, but talks to C and D. That's 2 more conversations.

    C can't talk to A or B, so talks to D. That's 1 more conversation.

    D has already spoken to everyone. That's 0 more conversations.

    There were 3+2+1 = 6 conversations.

  • 9 years ago

    12 conversations

  • 9 years ago

    12 conversations


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  • 9 years ago

    i'm pretty sure it's 12. Cause each person talked to 3 other people. there were 4 people. 4X3 =12

    Sorry if I'm wrong. didn't really try

  • 9 years ago

    a b c d

    ab ac ad

    bc bd


    = 6

  • 9 years ago


    6 Is right.. DUH

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