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Bunuel
How many positive integer unordered pairs are possible such that their least common multiple and the greatest common factor are 1530 and 51, respectively?

(A) 2
(B) 3
(C) 4
(D) 5
(E) 6
looking at lcm and gcd we can conclude that both numbers will have 3 and 17 as common and remaining 2 , 3 , 5 can be given to both numbers in any manner. now each number from 2 ,3 , 5 has 2 options to go to so total ways we can assign them is 8. since unordered pairs are asked we divide them by 2 to avoid repeated cases. hence answer is 4(C). is my reasoning correct ?
Yes, or you can think one number will always have \(17*3^2\) and the other will always have \(17*3\)

Now 5, and 2, can split in 4 ways.
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