If a paticulat yogurt has 75 vampires in 2 ounces how many would be in 8 ounces

8 divided by 2 = 4

==> You need to take 2 ounces 4 times in order to make 8 ounces.

But every time you take 2 ounces, you get 75 vampires along with it,

so you're also taking 75 vampires 4 times.

When you're done, you have (4 x 2) = 8 ounces of yogurt.

You also have (4 x 75) = 300 vampires.

(I have no idea what any of this means, and I would not eat your yogurt.)

300 vampires because you would need to multiply 2 ounces by 4 to get to 8 ounces. You then need to do the same with 75, giving you 300 vampires.