- Iron filings are made of small pieces of iron
- Iron is always magnetic
- So, iron fillings are always magnetic

- Iron fillings are always magnetic
- Sand is always nonmagnetic
- So, a mixture of iron fillings and sand is a mixture of magnetic and nonmagnetic material

- A mixture of iron fillings 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 fillings from sand

Therefore, a magnet can be used to separate iron fillings from sand
[Question]Which of these will best separate iron filings from sand?
[Context]- Iron filings are made of small pieces of iron 
- Iron is always magnetic 
- Magnet can be used for separating a magnetic material from a mixture of a magnetic and nonmagnetic material 
- Sand is always nonmagnetic