A vertical cylindrical vessel has a layer of kerosene (of density 800 kg/m³) over a layer of water (of density 1000 kg/m³). L-shaped glass tubes are connected to the column 30 cm apart. The interface between the two layers lies between the two points at which the L-tubes are connected. The levels (in cm) to which the liquids rise in the respective tubes are shown in the figure below. The distance (x in cm, rounded off to the first decimal place) of the interface from the point at which the lower L-tube is connected is _______