There are 6 kittens when you're deciding which one you want to pick, so there are 6 ways of chosing one. Then, the number of kittens lowers to 5, so there are 5 ways of picking another. At all, there are 30 ways of chosing 2 kittens out of 6.
Let

be the number Zabato is thinking of.



So the number is 2.
If there is 20 apples to 10 pears. you could say this as a ratio of 20:10 and then simplify this to 2:1.
<span>This means for every 2 apples there is 1 pear.</span>