Given,
Height of the tank =5m
Height of water filled=H= 2.5m
Density of water=X= 1000kg/M3
Pressure by water= HX x g
= 2.5 x 1000 x 9.81 = 24.5 KPa
Height of oil filled=h= 2.5m
Density of oil = x = 850kg/M3
Pressure by oil= hx x g
= 2.5 x 850 x 9.81 = 20.825 KPa
Hence total pressure = 24.5+20.825
=45.325KPa