Final Answer:
A magnet would not be useful in separating this mixture.
Step-by-step explanation:
A magnet is ineffective for separating sand, salt, and trenings because none of these components are magnetic materials. Sand is composed of minerals like silica and quartz, which are non-magnetic. Salt, typically sodium chloride, and trenings (assuming it's a typo or a term not recognized) are also non-magnetic substances.
One method to separate the mixture is through a process called filtration. Since sand is insoluble in water, it can be separated by pouring the mixture into water, allowing the sand to settle at the bottom, and then decanting the water. The salt and trenings would remain dissolved in the water, which can be further evaporated to retrieve the salt.
For separating salt and trenings, one could employ a process like evaporation or distillation. Both substances can be dissolved in water, but they might have different boiling points, allowing for separation through heating and condensation.
However, using a magnet in this scenario wouldn't aid in separation as it is not applicable to the properties of these substances. To effectively separate them, methods like filtration, evaporation, or distillation based on their physical properties would be more suitable.