How can you separate the mixture of sand water and salt

Answer: Salt is soluble in water, when salt is added to water most of it dissolves to make a solution. When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture. Salt can be separated from a solution through evaporation. The water can also be recovered as well as the salt if the water vapour is trapped and cooled to condense the water vapour back into a liquid. This process is called distillation.

Filtration to filter sand and the solution of salt+water then evaporation to separate salt from water.