A vertical cylindrical vessel has a layer of kerosene (of density $800\: kg/m^{3}$) over a layer of water (of density $1000 \:kg/m^{3}$). $L$ – 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 _________