The weight is the product of the mass [tex]m[/tex] of the body and the gravity acceleration [tex]g[/tex]:
[tex]W=m.g[/tex] (1)
Where [tex]g[/tex] is the acceleration due gravity with a value of [tex]9.8\frac{m}{s^2}[/tex] for the Earth
If we want to find the mass, we have to find [tex]m[/tex] in equation (1):
[tex]m=\frac{W}{g}[/tex] (2)
[tex]m=\frac{1323N}{9.8\frac{m}{s^2}}[/tex] (3)
Finally:
[tex]m=135kg[/tex]