LCM of N1 and N2 is 100, then find the possible pairs of N1 and N2?

26 10 18 13

13

LCM = 100 Prime factorization of 100 = 22 × 52                                    N = ax × by               Number of pairs = \(\frac{(2x \;+\; 1) (2y\; +\; 1) \;+\; 1}{2}\)                                       = \(\frac{(2 × 2 + 1) (2 × 2 + 1) + 1}{2}\) = \(\frac{26}{2}\) = 13