Let m and n,(m n) be two 2-digit numbers. Then the total numbers of pairs (m, n) , such that gcd(m, n)=6 , is ________

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Let m=6 a, n=6 ~b m n a b where a \& ~b are co-prime numbers also since m \& n are 2 digit nos, so 10 ≤ m ≤ 99 \& 10 ≤ n ≤ 99 i.e. 2 ≤ a ≤ 16 \& 2 ≤ b ≤ 16 ( a is integer) Now 2 ≤ a b ≤ 16 \& a \& ~b are co-prime if a=2, ~b=3,5,7,9,11,13,15 a=3, b=4,5,7,8,10,11,13,14,16 a=4, b=5,7,9,11,13,15 a=5, b=6,7,8,9,11,12,13,14,16 a=6, ~b=7,11,13 a=7, ~b=8,9,10,11,12,13,15,16 a=8, ~b=9,11,13,15 a=9, b=10,11,13,14,16 a=10, ~b=11,13 a=11, ~b=12,13,14,15,16 a=12, ~b=13 a=13, b=14,15,16 a=14, ~b=15 a=15, ~b=16 64 ordered pairs

Let m and n,(m n) be two 2-digit numbers. Then the total numbers of...

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