Answer:
The weight of the combined system is 1989.8 N.
Explanation:
The weight, W, of an object can be expressed as;
W = mg
where m is the mass of the object, and g is the acceleration due to gravity.
Weight of the combined system = weight of tank + weight of water
mass of the plastic tank = 3 kg
weight of the plastic tank = m x g
                = 3 x 9.8
                = 29.4 N
Weight of the plastic tank is 29.4 N
But,
density = [tex]\frac{mass}{volume}[/tex]
mass = density x volume
volume of water = 0.2 [tex]m^{3}[/tex], density of water = 1000 kg/[tex]m^{3}[/tex].
mass  = 1000 x 0.2
     = 200
mass of water = 200 kg
weight of water = 200 x 9.8
          = 1960 N
Thus,
combined weight of the system = 29.4 + 1960
            = 1989.8 N
The weight of the combined system is 1989.8 N.
