A={1,2,…,10}B{nm=m,n∈A,m<n,gcd(m,n)=1}n(B) n=2{21} n=3{31,32} n=4n=5{41,43}{51,52,53,54} n=6n=7n=8{61,65}{71,72,73,74,75,76}{81,83,85,87} n=9n=10n(B)=31{91,92,94,95,97,98}{101,103,107,109}
Let A={1,2,3,…,10} and B={nm:m,n∈A,m<n and gcd(m,n)=1}. Then n(B) is equal to :
Held on 22 Jan 2025 · Verified 6 Jul 2026.
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