This is a question volumetric flow rate.
In 1 second, water rises with 0.4 in.
Additionally,
Volume filled in 1 second = A*0.4, A = surface area of the circular cylinder.
Where,
A = πR^2 = π*3^2 = 9π in^2
Therefore,
Volumetric flow rate = 9π*0.4 = 11.31 in^3/s
In terms of liters/s,
1 in^3 = 0.0163871 litres
Then,
11.31 in^3/s = 11.31*0.0163871 ≈ 0.19 l/s