Answer:
![\rho _(oil)<\rho _(plastic)<\rho _(water)](https://img.qammunity.org/2021/formulas/chemistry/college/ari3t6x9ia0dajl45aik20kszha0bcjcj4.png)
Step-by-step explanation:
Hello,
In this case, since water and oil are immiscible due to the oil's nonpolarity and water's polarity, when mixed, the oil remains on the water since it is less dense than water. In such a way, for a plastic sunk in the oil and floating on the water (in middle of them) we can conclude that the plastic have a mid density, therefore, the required organization is:
![\rho _(oil)<\rho _(plastic)<\rho _(water)](https://img.qammunity.org/2021/formulas/chemistry/college/ari3t6x9ia0dajl45aik20kszha0bcjcj4.png)
Best regards.