- Sand is always nonmagnetic
- Iron is always magnetic
- Therefore, a mixture of iron and sand is a mixture of magnetic and nonmagnetic material

- A mixture of iron and sand is a mixture of magnetic and nonmagnetic material
- Magnet can be used for separating a magnetic material from a mixture of a magnetic and nonmagnetic material
- Hence, a magnet can be used to separate iron from sand

Hence, a magnet can be used to separate iron from sand
Question
Sand and iron particles that are similar in size and color are mixed together in a beaker. What would be the best method of separating the particles?

Context
- Sand is always nonmagnetic 
- Magnet can be used for separating a magnetic material from a mixture of a magnetic and nonmagnetic material 
- Iron is always magnetic