Answer:
496.57492 kg/m³
Step-by-step explanation:
= Atmospheric pressure = 101300 Pa
= Density of water = 1000 kg/m^3
= Height of water = 21.8 cm
= Height of fluid = 30 cm
g = Acceleration due to gravity = 9.81 m/s²
= Density of the unknown fluid
Absolute pressure at the bottom

The density of the unknown fluid is 496.57492 kg/m³