Here where you label the y and slope
The volume of the tank is (70 cm)³ = 343,000 cm³.
Now,
1 mL = 1 cm³
1 L = 1000 mL
so we convert the given rate to

Then the time it will take to fill up the tank is

50 becacause there is 27 and you need to add it all together
There is no given data table but based on the question, the reaction is
xy <=> x + y
If we let M as the initial concentration of xy and c as the in the concentration after the dissociation, then we can use the ICE method
xy <=> x + y
I M
C -c c c
-----------------------------
E M-c c c
Solve for c using
Kc = c(c) / (M - c)
And the concentration of the xy, x, and y can then be determined