All we have to do in this problem is find out how many times you are multiplying the original ratio by, then multiply the number next to the blank by the amount we are multiplying it by.
For example, question 1 shows us that you multiply 2 by 12 to get 24. That means that you will also have to multiply 3 by 12 to get you answer, which is 36.
The second one we are multiplying by 20, and we end up with the blank being 40. On the third one, we are multiplying by 26, and our answer is 78. For the fourth one, we are multiplying by 32 so our answer is 64.