Ok well first of all we need to calculate how many servings one batch of snack mix is, so we need to add the measurements for all the ingredients:
2.5 + 4.5 + 2.25 + 0.75 = 10 cups
Now calculate how many cups we should produce in order to make 200 servings:
0.75*200 = 150 cups
So now we know that we need to produce 150 cups of snack mix and that each batch can make 10 cups, so we can divide 150 by 10 to get to the conclusion that we must make 15 batches. Hopefully that makes sense :)