SOLUTION: Amy and Bill are two of the 10 people joining a massive online game. If two people are to be selected at random as group leaders, find the probability that both Amy and Bill are s

Question 1190820: Amy and Bill are two of the 10 people joining a massive online game. If two people are to be selected at random as group leaders, find the probability that both Amy and Bill are selected.
Answer by ikleyn(52864) (Show Source): You can put this solution on YOUR website!
.
Amy and Bill are two of the 10 people joining a massive online game.
If two people are to be selected at random as group leaders, find the probability
that both Amy and Bill are selected.
~~~~~~~~~~~~~~~~~

In all, there are   =  = 45 possible pairs that can be selected as leaders.


Of these 45 pairs, only one pair is (Amy,Bill).


So the probability that the pair (Amy,Bill) is selected, equals  .    ANSWER

Solved.

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This problem is on COMBINATIONS.

On Combinations, see introductory lessons
    - Introduction to Combinations
    - PROOF of the formula on the number of Combinations
    - Problems on Combinations
    - OVERVIEW of lessons on Permutations and Combinations
in this site.

Also, you have this free of charge online textbook in ALGEBRA-II in this site
    - ALGEBRA-II - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic "Combinatorics: Combinations and permutations".

Save the link to this textbook together with its description

Free of charge online textbook in ALGEBRA-II
https://www.algebra.com/algebra/homework/complex/ALGEBRA-II-YOUR-ONLINE-TEXTBOOK.lesson

into your archive and use when it is needed.

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