To develop this problem use the concept of the sum given pressure in the tank. At the bottom of the tank the pressure of this will be given by atmospheric pressure, the pressure given by the oil and the pressure by the water, that is to say that mathematically the pressure would be
[tex]P = P_{atm}+\rho_{oil}gt+\rho_{water}gh[/tex]
Note: Here the pressures are expressed in terms of density ([tex]\rho[/tex]), gravity (g) and thickness (t) or height (h). If we rearrange this equation to find the oil thickness we will have to,
[tex]\rho_{oil}gt = P-P_{atm}-\rho_{water}gh[/tex]
[tex]t = \frac{P-P_{atm}-\rho_{water}gh}{\rho_{oil}g}[/tex]
Our values are given as,
[tex]h = 0.84m[/tex]
[tex]P= 113kPa[/tex]
[tex]P_{atm} = 1.013*10^5Pa[/tex]
[tex]g = 9.8m/s^2[/tex]
[tex]\rho_{water} = 1000kg/m^3[/tex]
[tex]\rho_{oil} = 920kg/m^3[/tex]
Replacing we have that the thickness of the oil is:
[tex]t = \frac{P-P_{atm}-\rho_{water}gh}{\rho_{oil}g}[/tex]
[tex]t = \frac{113*10^3-1.1013*10^5-(1000)(9.8)(0.84)}{(920)(9.8)}[/tex]
[tex]t = 0.5947m[/tex]
Therefore the thick of the oil is 0.5947m
