Doubt from fluids

I'm getting 800ltr but answer given is 1200ltr

Amount of water in side the container is
Now as the container is given an acceleration
Find new hight of water level=1.6m
That means water will not leak through tap as water level is lower than tap(0.4m)
Now find the volume of new figure you'll get 4800L
So water leaked is 1200L