how many two person conversation can 30 people have?

Question

anyone know?

Answer 1

C(30,2) = "30 choose 2"
= 30! / (30-2)! 2!
= 30! / 28! 2
= 30 x 29 / 2

Here's a simple way to think of it:

There are 30 choices for the first person to include in the conversation and 29 for the second person. This would be 30 x 29, but the order doesn't matter (if I pick Anne first and then Bob, it's the same as picking Bob first and then Anne). It's just one pairing of people. So divide by 2.

( 30 x 29 ) / 2 = 435 conversations

Answer 2

Question is how many pairs of people are possible from a group of 30. Each of the 30 has a choice of 29 with whom to talk or30*29=870. this has to be divided by 2 since person a talking to person c is the same as person c talking to person a etc.
Answer is 29*30/2=435.

Answer 3

435
because 30 people means 15 two people conversations and one person can have conversation with 29 other people
therefore
15 x 29 = 435 converstaions

Answer 4

2^30 converstaions

Answer 5

435 - add up 29+28+27+....+2+1

Answer 6

if you can talk to only one person at a time, then the answer is 15