Answer 1= 1:3, 2:6, 4:12 and 8:24 are all possible ratios.
Answer 2= 1/3, 2/6, 4/12 and 8/24. These fractions represent parts of a whole, as well as the ratios.
The simplest forms are 1/3 and 1:3. The most complex forms are 8:24 and 8/24. Anything else you need?