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Math Prize For Girls Problems
2021 Math Prize for Girls Problems
18
18
Part of
2021 Math Prize for Girls Problems
Problems
(1)
Math Prize 2021 Problem 18
Source:
9/19/2021
Let
N
N
N
be the set of square-free positive integers less than or equal to 50. (A square-free number is an integer that is not divisible by a perfect square bigger than 1.) How many 3-element subsets
S
S
S
of
N
N
N
are there such that the greatest common divisor of all 3 numbers in
S
S
S
is 1, but no pair of numbers in
S
S
S
is relatively prime?
Math Prize for Girls