I don't know if I'm going nuts or not, but I've done a question in the textbook and I'm not getting the same answer and I have no idea why.

Calculate the empirical formulae:

3.5g of silicon combined with 4.0g of oxygen

I did 3.5/14 and 4.0/16 and got 0.25 for both, hence the empirical formulae being SiO, but the answers say SiO2 (silicon dioxide). Is this a typing error or what?