There are 6 spots for every 2 eyes. There are 3 spots for every 1 eye.
If we simply count the number of spots and eyes we get 6 spots and 2 eyes. If we simplify this by dividing each by 2 we see that there are 3 (6 divided by 2) spots for every 1 (2 divided by 2) eyes. 6:2 = 3:1