well, we know there are 16oz in 1lb, and we know there are 2.2lbs in 1Kg, so
[tex]\bf 25500~\underline{oz}\cdot \cfrac{1~\underline{lb}}{16~\underline{oz}}\cdot \cfrac{1kg}{2.2~\underline{lb}}\implies \cfrac{25500\cdot 1\cdot 1~kg}{16\cdot 2.2}\qquad \approx \qquad 724.43\overline{18}~kg[/tex]
