Suppose you pour water into a container until it reaches a depth of 12 cm. next, you carefully pour in an 8.5 cm thickness of olive oil so that it floats on top of the water.
what is the pressure at the bottom of the container?

the pressure at the bottom is approximately 103264 Pa

Explanation:

From Pascal's law, the pressure at the bottom of the container is the pressure from the atmosphere and the columns of water and olive , therefore

Pressure at the bottom = Pressure at the surface of the liquid ( atmospheric pressure) + pressure of the column of water + pressure of the column of olive oil

since

- Pressure at the surface of the liquid = atmospheric pressure = 101325 Pa

- pressure of the column of water = density of water * gravity * level of water

= 1000 kg/m³ * 9.8 m/s² * 0.12 m = 1176 Pa

- pressure of the column of olive oil=  density of olive oil* gravity * level of olive oil = 916 kg/m³ * 9.8 m/s² * 0.085 m = 763 Pa

therefore

Pressure at the bottom = 101325 Pa + 1176 Pa + 763 Pa = 103264 Pa

density of olive oil was taken from internet sources ( we can check that is lower than the one of water, and thus it floats )