The figure shows two fluids held by a hinged gate. The atmospheric pressure is $P_a=100 \mathrm{kPa}$. The moment per unit width about the base of the hinge is ____________ $\mathrm{kNm} / \mathrm{m}$. (Rounded off to one decimal place)
Take the acceleration due to gravity to be $\mathrm{g}=9.8 \mathrm{~m} / \mathrm{s}^2$.