Question 200902
Two different natural numbers are selected from the set {1,2,3,…,6}. What is the
probability that the greatest common factor of these two numbers is one? Express
your answer as a common fraction
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There are 6C2 = 15 distinct pairs of numbers.
The following pairs satisfy the criteria.
1,2;1,3;1,4;1,5;1,6
2,3;2,5
3,4;3,5
4,5
5,6
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P(pairs that meet the criteria) = 11/15 
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Cheers,
Stan H.