Answer:
The weight of the combined system is 2001.24 Newtons
Step-by-step explanation:
From the basic relation between mass, density and volume we know that

In our context we are given that the density of water is 1000 kg per cubic meters
Thus we can find the mass of 0.2 cubic meters of water using the above relation as

Hence the mass of water in the tank is 200 kilograms.
The total mass of water and the plastic tank thus becomes

Now we know that weight of any given mass is calculated as

where,
'g' is the acceleration due to gravity with value =

Applying the values in the above equation we get